Persistent Diplopia in Visually Mature Patients . Is it Intractable or something else ? A Review and Case Series

Correspondence regarding this article should be emailed to Robert P. Rutstein, OD, MS, FAAO at bagel@uab.edu. All state ments are the author’s personal opinions and may not reflect the opinions of the College of Optometrists in Vision Development, Vision Development & Rehabili tation or any institu tion or organization to which the author may be affiliated. Permission to use reprints of this article must be obtained from the editor.

Related papers:

title: Intractable diplopia following monocular patching
abstract: Although acquired strabismus in a visually mature adult typically causes double vision, this diplopia usually resolves if the eyes are realigned because of the patient's previous ability to fuse. In some adults, however, acquired strabismus and diplopia are secondary to a loss of fusional ability. Such patients can suffer from intractable diplopia, which is often more symptomatic if vision is improved and/or if the eyes are realigned. An illustrative case is presented and discussed.

title: Intractable diplopia: A clinical perspective
abstract: Eight patients with intractable diplopia are presented. A classification of intractable diplopia is proposed, as well as a possible unifying view of its pathogenesis. Currently available treatment modalities are reviewed.

title: Horror fusionis: a report of five patients.
abstract: Horror fusionis is an uncommon anomaly and is rarely reported in the literature.



Five adults with long-standing diplopia associated with horror fusionis were examined.



All patients had strabismus since early childhood and had been treated at that time either with surgery, occlusion, and/or orthoptics/vision therapy. Prisms could not eliminate the diplopia. Graded occlusion was attempted with one patient but was not tolerated. Another patient with an asymmetrical dissociated vertical deviation could ignore the second image by fixating with the eye with the smaller deviation. Two patients reported the diplopia becoming less noticeable over the years.



Because of its poor prognosis, the diplopia associated with horror fusionis must be differentiated from other types of diplopia occurring in adults with childhood onset strabismus.

title: The loss of fusion in adults with intractable diplopia (central fusion disruption).
abstract: People over the age of 10 years can lose their fusion ability. This acquired disruption of fusion gives rise to intractable diplopia without suppression. An involuntary vertical bobbing movement of the non-fixing eye, present only with both eyes open, occurs at or near the angle of superimposition. This appears to be a unique and characteristic sign of acquired disruption of fusion and was present in all cases. Other causes of diplopia are mentioned and differentiated. Acquired central fusion disruption usually results from serious head injury. Partial recovery may occur but is unlikely. Sensory deprivation of at least 3 1/2 years' duration due to poor vision in one eye resulting from a traumatic cataract and sometimes subsequent uncorrected unilateral aphakia caused loss of fusion in 15 patients. The practical implications with regard to intraocular lenses and unilateral aphakia is discussed. Less commonly, vascular, neoplastic and presumed inflammatory lesions in the mid-brain area cause central fusion disruption.

title: Sensory fusion disruption syndrome.
abstract: Unlike the typical manifestation of acquired strabismus, patients with sensory fusion disruption syndrome are unable to fuse targets even when bifoveally aligned under ideal clinical conditions. This condition usually follows trauma and a period of coma. These patients suffer from chronic diplopia which is not relieved by optical or surgical means. Recognition of this entity may result in more effectual management. As a phenomenon, it serves as a potential clue to physiological composition of binocularity.

title: Use of Bangerter filters with adults having intractable diplopia.
abstract: The aim of this study was to describe the use of Bangerter filters in adults having intractable diplopia.



A series of adults having intractable diplopia caused by either cyclotorsion, retinal disease, monocular diplopia, or rapid alternating fixation who were treated with Bangerter filters is reported. Detailed case reports on 4 of the 10 patients are included.



Bangerter filters can be used to mitigate diplopia that cannot be eliminated with either prism, modification of the spectacle prescription, vision therapy, or extraocular muscle surgery. The weakest density filter that eliminates the diplopia should be prescribed. Prospective studies reporting the long-term efficacy and quality of life with the filters are needed.

title: Nonsurgical management of binocular diplopia induced by macular pathology.
abstract: To treat binocular diplopia secondary to macular pathology.



Seven patients underwent evaluation and treatment. All had constant vertical diplopia caused by various maculopathies, including subretinal neovascularization, epiretinal membrane, and central serous retinopathy. Visual acuity ranged from 20/20 to 20/30 in the affected eye. All except 1 patient had a small-angle, comitant hyperdeviation with no muscle paresis. Sensory evaluation demonstrated peripheral fusion and reduced stereoacuity. Neither prism correction nor manipulation of the refractive errors corrected the diplopia. A partially occlusive foil (Bangerter) of density ranging from 0.4 to 1.0 was placed in front of the affected eye to restore stable, single vision.



The Bangerter foil eliminated the diplopia in all patients. Two patients elected not to wear the foil; 1 patient was afraid of becoming dependent, and the other was bothered by the visual blur. Visual acuity in the affected eye was reduced on average by 3 lines. All patients maintained the same level of sensory fusion, with only 2 having reduced stereoacuity. Symptoms returned when the foil was removed or its density was reduced.



Low-density Bangerter foils provide an effective, inexpensive, and aesthetically acceptable management for refractory binocular diplopia induced by macular pathology, allowing peripheral fusion to be maintained.

title: Monovision correction for diplopia.
abstract: Acquired, incomitant strabismus frequently results in diplopia. Affected patients complain of chronic annoyance and frustration with the false image. Therapy has usually been aimed at either re-establishing binocularity by using prisms or vision training, or by eliminating one image through occlusion. An alternative approach is to allow each eye its own "domain," one eye corrected for distance vision and the other for near vision. This alternative may eliminate the competitive, unfusible images and yet maintain visual function in each eye.

title: A Unique Use for a Corneal Tattoo
abstract: Corneal tattoos have been previously used in managing corneal pathologies.  We describe a case of a 28-year-old male who presented with intractable binocular diplopia, which was relieved with a corneal tattoo.  This is a novel application of corneal tattooing for the alleviation of intractable binocular diplopia.

title: Opaque Intraocular Lens for Intractable Diplopia—UK Survey
abstract: To assess the practice of the use of an opaque intraocular lens (IOL) for intractable diplopia in the UK.  A questionnaire was sent to 892 consultant ophthalmologists in practice requesting information on the treatment of intractable diplopia with an opaque IOL. Respondents were asked whether they would consider using an opaque IOL for intractable diplopia. Information was gathered on the numbers of lenses implanted, the type of lens used, and whether the lens was implanted inside or outside the capsular bag. In addition, we asked for the causes of intractable diplopia, the success in eliminating diplopia, the use of postoperative pilocarpine, and whether postoperative surveillance was part of the follow-up protocol.  Of the 481 completed questionnaires received, 72% would consider implanting an opaque IOL. A total of 48 surgeons had implanted 1 or more lenses. There were 97 patients who were implanted with an opaque IOL over the past 15 years. Strabismus, nerve palsies, and previous retinal detachment surgery with diplopia were the main indications. Pseudophakic lenses were used by 38 surgeons in the capsular bag, 6 used iris-supported phakic lenses, and 2 used phakic lenses in the anterior chamber angle. The use of postoperative pilocarpine was reported by 9 surgeons, and 6 surgeons used regular ultrasound fundal surveillance. Patients were reported to be completely asymptomatic at discharge by 31 surgeons, with 15 surgeons reporting patients who were still symptomatic postoperatively. Only 1 intraoperative complication was reported.  An opaque IOL is a safe method for treating intractable diplopia. This survey confirms that its practice is widely accepted in the UK.

title: Opaque intraocular lens for intractable diplopia: experience and patients’ expectations and satisfaction
abstract: To report the authors' experience with the use of opaque intraocular lenses (IOL) in diplopia unresponsive to traditional management strategies, and to assess patients’ satisfaction and the visual function of patients following insertion of opaque IOL using the Visual Function Index (VF-14).  Royal Victoria Infirmary, Newcastle upon Tyne, UK.  Data were obtained on all patients who underwent insertion of an opaque IOL at our institution between 2002 and 2006. Patients were interviewed by telephone. Any visual function impairment was assessed using the VF-14 questionnaire. Patients were also asked to score subjectively their overall satisfaction with the visual outcome after opaque IOL insertion.  The authors studied 12 patients (n = 12) who had insertion of opaque IOL. All patients had constant and persistent diplopia unresponsive to other treatments acceptable to the patient. The median duration of diplopia was 5.5 years (interquartile range was 2.4–17.3 years). The postoperative VF-14 ranged from 75 to 100, and the mean VF-14 was 91 (95% CI 83–99). Three patients reported a maximum score of 100. Patient satisfaction ranged from 2 to 4, and the average was 3.4 out of 4.  Opaque IOL insertion is a valuable option in the management of intractable diplopia. The VF-14 revealed very little or no impairment in visual function following the procedure. All patients reported improvement in their visual function and were pleased with the final outcome.

title: Strabismus surgery for adults: a report by the American Academy of Ophthalmology.
abstract: To describe the effectiveness and safety of surgical treatment of adult patients with strabismus, and to review the reported functional benefits and complications of strabismus surgery for adults.



A literature search was conducted in September 2001. It was repeated and updated in April 2003, with retrieval of relevant citations. Panel members reviewed the articles and rated them according to their relevance to the topic and methodology.



The literature search identified 49 reports that describe the surgical treatment of strabismus in adult patients and meet predetermined review criteria. Of these reports, 2 were of randomized controlled trials, and 1 addressed the primary objective of this review. In this randomized study of adults with strabismus, direct comparison of surgical correction with botulinum toxin A chemodenervation indicated that surgical treatment was superior to botulinum toxin A in realigning the eyes (76.9% vs. 29.4%, P = 0.027). Several large case series of adults with strabismus (level III evidence) with successful surgical realignment rates of 68% to 85% have been reported. Functional benefits of surgical treatment are reported in many patients. These include elimination of diplopia, development of binocular fusion, expansion of binocular visual fields, and improvement of head position. Surgical complications, including new, postoperative diplopia (1%-14%) or scleral perforation (0.8%-1.8%), occur in a minority of patients. Unplanned reoperations (subsequent strabismus procedures that were not anticipated as part of a staged treatment) were needed in up to 21% of patients in large case series of comitant strabismus, and in up to 50% of patients with thyroid ophthalmopathy.



Despite the paucity of level I evidence from randomized controlled trials, the existing literature suggests that surgical treatment of adults with strabismus is safe and effective in improving ocular alignment. In many cases it improves visual function, based largely on level III evidence. Risks include unplanned reoperation, postoperative diplopia, and scleral perforation. Additional level I studies of surgical treatment of adult patients would help to document the effectiveness and substantiate the safety of this treatment.

title: Diplopia After Strabismus Surgery
abstract: The presence of diplopia is an undesirable result following strabismus surgery. There are a variety of scenarios where diplopia exists prior to strabismus surgery, and, after surgery, has been either alleviated or decreased to a magnitude amenable to prism correction. In other cases, the patient does not experience diplopia prior to the strabismus surgery, but there exists a definite risk of diplopia after the surgery. In the current review, I examine the literature to help determine the incidence of diplopia after strabismus surgery.

title: Intractable diplopia after strabismus surgery in adults.
abstract: To investigate the incidence of persistent intractable diplopia in adults undergoing surgery for long-standing, constant strabismus and to define tests that may be useful for identifying patients at risk for developing this complication.



A retrospective medical record review of adults without diplopia undergoing surgery for constant strabismus.



Medical records of 424 adult patients undergoing strabismus surgery were studied. Of these patients, 143 (34%) experienced diplopia when tested preoperatively with prisms to simulate the desired surgical outcome. Only 40 patients (9%) had temporary diplopia after surgery, which resolved in all cases by 6 weeks postoperatively. Three patients (0.8%) developed persistent intractable diplopia. Experiencing diplopia with preoperative prism testing was significantly more likely to result in postoperative diplopia than if diplopia was not present preoperatively (P<.001 and P =.04 for temporary and persistent postoperative diplopia, respectively). Preoperative testing had a sensitivity and negative predictive value for temporary postoperative diplopia of 100%, a specificity of 73%, and a positive predictive value of 28%. Similar values were found for persistent diplopia after surgery with the exception of the positive predictive value, which was only 2%. Patients who did not see double during preoperative testing with prisms never developed diplopia after surgery. However, the presence of preoperative diplopia with prism testing (including a prolonged trial with Fresnel prisms) was infrequently predictive of postoperative diplopia.



Intractable diplopia after strabismus surgery in adults without previous diplopia is very rare. The diagnostic use of prisms prior to surgery may identify some patients who have little or no risk of postoperative diplopia, as well as a group of patients with a small but definite risk of intractable postoperative diplopia.

title: Monocular central-field occlusion for intractable diplopia.
abstract: This report describes several methods of degrading imagery through the central portion of a spectacle lens to provide a cosmetically acceptable means of obtaining single vision in the central field of patients with intractable diplopia. For 2 strabismic patients with annoying diplopia, we applied to 1 spectacle lens a centrally placed disc (about 1 inch diameter) consisting of (1) translucent tap,a (2) a +7 D Fresnel lens,b or (3) stippled, clear lacquer. For 1 patient, the lacquer was the most acceptable; for the other, the tape was best. We present here the case reports for these 2 patients, showing why they preferred different image-degrading methods and how these and other methods of central-field image degrading can be advantageous even when diplopia is present across most of the visual field.

title: Fusion ability lost and regained in visual adults
abstract: The case reports are given of two adult patients who lost all fusion ability and had the signs and symptoms of central fusion disruption and intractable diplopia. Both patients suffered binocular sensory deprivation for several years caused by a combination of a traumatic cataract and uncorrected unilateral aphakia. One patient had a posterior chamber intraocular lens inserted to correct the aphakia and the other patient had a contact lens. Aniseikonia was not appreciated by either patient and did not appear to contribute to the fusion problem. Adjustable strabismus surgery, in both patients, and prism glasses, in one, enabled approximate superimposition of the visual axes.After several months, both patients began to develop some fusion with small amplitudes and the vertical bobbing typical of central fusion disruption disappeared.

title: Intractable diplopia after vision restoration in unilateral cataract.
abstract: Twenty-four patients lost their ability to fuse when their binocular function was disrupted for at least 2 1/2 years by a unilateral traumatic cataract or a unilateral traumatic cataract followed by uncorrected aphakia. Three patients were 6 years old, one was 8 years old, and the remaining 20 patients were aged 10 years or older at the time of the injury. All patients had intractable diplopia when the cataract was removed and the aphakia corrected. Aniseikonia was not the cause of this inability to fuse and the insertion of an intraocular lens provided no relief. The prognosis for the elimination of diplopia, other than by occlusion of one eye, was poor.

title: Risk factors of persistent diplopia following secondary intraocular lens implantation in patients with sensory strabismus from uncorrected monocular aphakia
abstract: PurposeWe aimed to compare clinical characteristics between diplopia-free and diplopia-persistent patients after successful strabismus surgery, when patients complained of diplopia following secondary intraocular lens (IOL) implantation after prolonged aphakia accompanied by sensory strabismus.MethodsRetrospective review of medical records of patients who complained of diplopia following secondary IOL placement with sensory strabismus after prolonged uncorrected monocular aphakia from isolated ocular trauma was done. We classified patients into two groups according to persistency of diplopia, 6 months after successful strabismus surgery. Clinical characteristics were compared between groups. total of 31 patients were included. The diplopia-persistent group showed longer duration of uncorrected aphakia (p = 0.02), less severe corneal astigmatism (p = 0.04), a smaller exodeviation angle (p = 0.02), and more frequent vertical deviation (p = 0.015), extorsion (p = 0.022) and monocular nystagmus (p = 0.028) than the diplopia-free group. In all patients in the diplopia-free group, diplopia could be eliminated prior to strabismus surgery using loose prisms in free space, whereas seven patients in the diplopia-persistent group prior to surgery could not resolve diplopia.ConclusionsOur data will be helpful for ocular surgeons in determining whether to insert secondary IOL in prolonged aphakia with sensory strabismus, or whether strabismus surgery will eliminate diplopia that develops following secondary IOL placement in this situation.

title: Acquired central fusion disruption following cataract extraction.
abstract: Central sensory and motor fusion of images, once established, is usually maintained throughout life. Under certain circumstances, this ability may be lost. This gives rise to the syndrome known as horror fusionis, or acquired disruption of central fusion. We report the development of central fusion disruption in three patients with uniocular mature senile cataract. We postulate that this is the result of prolonged sensory deprivation in the cataractous eye. The loss of fusion results in a particularly troublesome type of intractable diplopia, characterized by the inability to either fuse or suppress images. To the best of the authors' knowledge, this is the first report of central fusion disruption following cataract surgery for senile cataract.

title: Anomalies of binocular vision : diagnosis and management
abstract: Chapter 1. Normal and Abnormal Binocular Vision Chapter 2. Amblyopia Chapter 3. Anomalies of Accommodation Chapter 4. Aniseikonia Chapter 5. Suppression and Anomalous Correspondence Chapter 6. Heterophoria and Vergence Anomalies Chapter 7. Strabismus Chapter 8. Esotropia Chapter 9. Exotropia Chapter 10. Incomitant Deviations Chapter 11. Medical and Surgical Management of Strabismus Chapter 12. Binocular Vision in Private Practice Chapter 13. Liability Issues in Binocular Vision Practice

title: The benefits, risks, and efficacy of strabismus surgery in adults.
abstract: Strabismus surgery in adults achieves satisfactory alignment with one operation in approximately 80% of patients, depending on the specific nature of the problem. Risks of adult strabismus surgery are relatively low, and serious complications are anecdotal and rare. Even if the strabismus has been long-standing, most adults will experience some improvement in binocular function after strabismus surgery. Consequently, adult strabismus surgery should not be considered merely cosmetic in most cases. In esotropic patients, this improvement typically takes the form of an expansion of binocular visual fields; however, some patients may also regain stereopsis. There are many psychosocial benefits to adult strabismus surgery. This is reflected in the finding that the majority of adults surveyed with strabismus would trade a portion of their life expectancy to be rid of their strabismus.

title: Obstacles to Fusion: Strabismus and Diplopia
abstract: There are many potential obstacles to fusion for adult patients with diplopia. Monocular diplopia is the first obstacle that should be ruled out in every adult patient before they are referred for a complete sensorimotor evaluation. Monocular diplopia is usually refractive in nature, but may also be the result of an ocular defect, or, in rare cases, the problem may be neurologic. Obstacles to motor fusion include: incomitant strabismus, insufficient fusional amplitudes, torsion, and nystagmus. Obstacles to sensory fusion include image disparity and sensory anomalies such as suppression, ARC, and eccentric fixation. Sensory anomalies are the most difficult to treat and can result in intractable diplopia.

title: Diagnosis and management of monocular diplopia.
abstract: Monocular diplopia is a symptom which may range from a visual curiosity to being visually dehabilitating. Its proper diagnosis and management presents a challenge to the clinician. A comprehensive review of the literature illustrates the multiple etiologies which may produce this complaint. Differential diagnosis is an important factor in the ultimate successful management of the problem, since the latter is to a degree etiology specific. Method of differential diagnosis and management options are discussed.

title: Causes and outcomes for patients presenting with diplopia to an eye casualty department
abstract: PurposeTo evaluate the causes and outcomes for patients presenting with diplopia to an eye casualty department.MethodsPatients presenting with diplopia as a principal symptom, who were referred to the Orthoptic Department from Moorfields Eye Casualty over a 12-month period, were retrospectively investigated.ResultsOne hundred and seventy-one patients were identified with complete records in 165 cases. There were 99 men and 66 women with an age range of 5–88 years. Monocular diplopia accounted for 19 cases (11.5%), whereas 146 patients (88.5%) had binocular diplopia. Cranial nerve palsies were the most common cause of binocular diplopia accounting for 98 (67%) of cases. Isolated sixth nerve palsy was the largest diagnostic group (n=45). Microvascular disease (hypertension or diabetes mellitus, or both) was present in 59% of patients with cranial nerve palsies, and of this group, 87% resolved spontaneously by 5 months rising to 95% by 12 months.ConclusionPatients with clinically isolated single cranial nerve palsies associated with diabetes or hypertension are likely to recover spontaneously within 5 months and initially require observation only. However, patients with unexplained binocular diplopia and those who progress or fail to recover should be investigated to establish the underlying aetiology and managed as appropriate.

title: Monocular diplopia accompanying ordinary refractive errors.
abstract: Monocular diplopia is commonly encountered in ophthalmic practice. We discovered that it could be induced in nine (82%) of 11 normal eyes with ordinary spherical or astigmatic defocus of the retinal image. Possible mechanisms responsible for this effect include retinal processing, diffraction effects, and spherical aberration. By employing geometric blur circle theory and using a simple optical model to photograph the effect, we concluded that monocular diplopia in the setting of ordinary refractive error is secondary to relatively minor optical irregularity such as spherical aberration. Contour enhancement properties of the retina probably accentuate this effect. Ordinary refractive error should therefore not be overlooked or discounted in patients with monocular diplopia.

title: Monocular diplopia due to spherocylindrical refractive errors (an American Ophthalmological Society thesis).
abstract: Ordinary spherocylindrical refractive errors have been recognized as a cause of monocular diplopia for over a century, yet explanation of this phenomenon using geometrical optics has remained problematic. This study tests the hypothesis that the diffraction theory treatment of refractive errors will provide a more satisfactory explanation of monocular diplopia.



Diffraction theory calculations were carried out for modulation transfer functions, point spread functions, and line spread functions under conditions of defocus, astigmatism, and mixed spherocylindrical refractive errors. Defocused photographs of inked and projected black lines were made to demonstrate the predicted consequences of the theoretical calculations.



For certain amounts of defocus, line spread functions resulting from spherical defocus are predicted to have a bimodal intensity distribution that could provide the basis for diplopia with line targets. Multimodal intensity distributions are predicted in point spread functions and provide a basis for diplopia or polyopia of point targets under conditions of astigmatism. The predicted doubling effect is evident in defocused photographs of black lines, but the effect is not as robust as the subjective experience of monocular diplopia.



Monocular diplopia due to ordinary refractive errors can be predicted from diffraction theory. Higher-order aberrations--such as spherical aberration--are not necessary but may, under some circumstances, enhance the features of monocular diplopia. The physical basis for monocular diplopia is relatively subtle, and enhancement by neural processing is probably needed to account for the robustness of the percept.

title: Diplopia Associated with Refractive Surgery
abstract: When diplopia occurs after refractive surgery, a systematized approach to diagnosis and treatment is useful. First, determine if the problem is monocular or binocular. Monocular diplopia usually is caused by anterior segment complications and should be referred to an anterior segment surgeon. If the problem is binocular, determine if there is iatrogenic monovision. If monovision was created by the refractive surgery, determine if the double vision is due to fixation switch diplopia. If so, the monovision state needs to be reversed. If fixation switch is not the cause of the symptoms, try “optical rescue.” If monovision is not present, check old refraction and motility records, and correct any residual refractive error. Strabismus may need to be treated with surgery, orthoptic exercises, or prisms.

title: Recently acquired diplopia in adults with long-standing strabismus.
abstract: The evaluation and management of recent-onset diplopia in an adult with a history of long-standing strabismus can be perplexing and challenging. No guidelines exist, to my knowledge, for the examination of such patients.



A retrospective medical record review.



Patients seen in my practice with a history of recently acquired diplopia and a history of strabismus dating back to childhood.



One hundred fifty-two patients who met the enrollment criteria were identified. Using the treatment approach outlined herein, 132 patients were relieved of their symptoms of diplopia. In most cases, the onset of the diplopia could be correlated with a change in the patient's ocular alignment, refractive needs, or refractive management. Returning patients to their motor status before the onset of symptoms or addressing the change in refractive needs or management usually resulted in relief of symptoms.



In most cases, adult patients with a history of long-standing strabismus and a recent onset of diplopia can be effectively treated.

title: A randomized trial comparing Bangerter filters and patching for the treatment of moderate amblyopia in children.
abstract: To determine whether visual acuity improvement with Bangerter filters is similar to improvement with patching as initial therapy for children with moderate amblyopia.



Randomized, clinical trial.



We enrolled 186 children, 3 to <10 years old, with moderate amblyopia (20/40-20/80).



Children were randomly assigned to receive either daily patching or to use a Bangerter filter on the spectacle lens in front of the fellow eye. Study visits were scheduled at 6, 12, 18, and 24 weeks.



Visual acuity in amblyopic eyes at 24 weeks.



At 24 weeks, amblyopic eye improvement averaged 1.9 lines in the Bangerter group and 2.3 lines in the patching group (difference in mean visual acuities between groups adjusted for baseline acuity = 0.38 line). The upper limit of a 1-sided 95% confidence interval was 0.76 line, which slightly exceeded a prespecified noninferiority limit of <0.75 line. Similar percentages of subjects in each group improved > or =3 lines (Bangerter group 38% vs patching group 35%; P = 0.61) or had > or =20/25 amblyopic eye acuity (36% vs 31%, respectively; P = 0.86). There was a lower treatment burden in the Bangerter group as measured with the Amblyopia Treatment Index. With Bangerter filters, neither a fixation switch to the amblyopic eye nor induced blurring in the fellow eye to worse than that of the amblyopic eye was required for visual acuity improvement.



Because the average difference in visual acuity improvement between Bangerter filters and patching was less than half a line, and there was lower burden of treatment on the child and family, Bangerter filter treatment is a reasonable option to consider for initial treatment of moderate amblyopia.

title: Visual acuity through Bangerter filters in nonamblyopic eyes.
abstract: To describe the amount of visual acuity degradation induced by Bangerter filters in the better seeing eye and to evaluate its stability over time in children with moderate amblyopia.



Visual acuity with and without a Bangerter filter was measured in the nonamblyopic eye of 186 children with moderate amblyopia who were then treated with either patching or the Bangerter filters. A 0.2 filter was used for amblyopia of 20/80 and a 0.3 filter for amblyopia from 20/40 to 20/63. For the 89 children randomized to Bangerter filters, visual acuity was also measured in the nonamblyopic eye with and without the filters at both 6 weeks and 12 weeks after initiating treatment.



Mean degradation in visual acuity of the nonamblyopic eye at baseline was 5.1 logMAR lines with the 0.2 filter and 4.8 logMAR lines with the 0.3 filter. The degradation with each filter did not always agree with the manufacturer's specifications. Over time, the amount of degradation with the filters decreased.



The 0.2 and 0.3 Bangerter filters degrade nonamblyopic eye visual acuity sufficiently in amblyopic children. Because the amount of degradation decreases over time, it is recommended to periodically apply a new filter when using this type of amblyopia treatment.

title: Fixation switch diplopia.
abstract: To present guidelines for the diagnosis and management of fixation switch diplopia.



Adults with a history of strabismus since childhood may experience acquired diplopia if a change in their refractive error or use of spectacles encourages fixation with their nondominant eye. This is referred to as "fixation switch diplopia." If correctly diagnosed, this seldom-recognized cause of acquired diplopia in adults can almost always be successfully treated with the proper optical management.



A retrospective review was carried out for all patients with the diagnosis of fixation switch diplopia who were seen in my private practice.



A review of patient records identified 16 patients with fixation switch diplopia. In four patients, the switch in fixation was spontaneous owing to the development of myopia in the previously preferred eye in patients with mild contralateral amblyopia. Six patients developed diplopia owing to their "monovision" (one eye optically corrected for distance and the other eye presbyopic). In six patients, fixation switch diplopia occurred because a noncycloplegic subjective refraction was performed in the presence of amblyopia, resulting in an unbalanced refractive correction. In all 16 patients, symptoms were eliminated when proper optical correction was instituted to encourage fixation with the dominant eye.



Fixation switch diplopia is a cause of acquired diplopia in adults with a history of strabismus since childhood. It can usually be successfully treated with proper optical management.

title: Diplopia after refractive surgery: occurrence and prevention.
abstract: To report the occurrence of persistent diplopia manifesting after refractive surgery, to describe the different causes of this complication, to provide risk stratification for its occurrence, and to outline minimal screening techniques for its prevention.



A retrospective medical record review of patients seen in 2 private strabismus practices who experienced persistent diplopia after refractive surgery.



A total of 28 patients were identified who met the inclusion criteria. The causes of postoperative diplopia could be traced to 1 of 5 mechanisms. These included technical problems, prior need of prisms, aniseikonia, iatrogenic monovision, and improper control of accommodation in patients with strabismus. The recommended screening techniques would have identified all patients in this series as being at risk for postoperative diplopia with the exception of those in whom technical problems were responsible.



Diplopia can become manifest after refractive surgery. With proper attention paid to risk stratification and recommended screening criteria, the incidence of this complication can be minimized.

title: Strabismus precipitated by monovision.
abstract: To present patients who had the onset of strabismus or the recurrence of strabismus after converting to a monovision system of seeing.



Retrospective interventional case series.



Clinical records of 12 patients from the private practice of the corresponding author of this paper (Z.F.P.) were reviewed. Patients obtaining monovision via contact lenses, LASIK, and cataract surgery with posterior chamber intraocular lenses were studied if their monovision produced a new strabismus or was related to the recurrence of a previous strabismus.



All patients were first treated by converting the monofixing near eye to distance vision and then using reading glasses for near work. Of the 12 patients, 7 regained their fusion by doing away with monovision and 5 required surgery to reestablish motor or sensory control. All of the surgery patients obtained an excellent alignment but 1 did not regain sensory fusion.



Monovision is successful for the far majority of patients who try it. However, in patients with a previous history of strabismus or those with significant phorias, caution should be used in recommending monovision, and if monovision is elected, keeping the anisometropia to small levels such as 1.25 to 1.50 diopters (D) might lessen the chance of producing strabismus post monovision. The majority of our patients developed strabismus after 2 years of monovision, telling us that while a trial of monovision with a contact lens prior to surgery may suggest that the patient could tolerate monovision, it is not a guarantee.

title: Fixation Switch Diplopia.
abstract: N ew-onset diplopia in an adult patient can be a highly concerning symptom that may trigger a neurologic or neuro-ophthalmic evaluation. Certainly, well-known causes of diplopia initially must be considered including ocular motor cranial nerve palsies, myasthenia gravis, and thyroid eye disease. However, when the diplopic patient has a history of childhood strabismus or amblyopia, the evaluation and management is different. Patients whose strabismic angle is unchanged or minimally changed, despite the new onset of diplopia, are particularly challenging. The differential diagnosis for new-onset diplopia in a patient with a history of childhood eye disease includes elimination of suppression in the amblyopic eye, a change in the angle of strabismus causing a drift outside the patient’s suppression scotoma, unmasking of diplopia that was previously masked by a cataract or ptosis, central disruption of fusion, or fixation switch diplopia. The focus of this editorial will be on the topic of fixation switch diplopia. Fixation switch diplopia occurs in patients with long-standing strabismus, who partially lose visual acuity in the fixating dominant eye, often as a result of cataract or refractive error (1). Because of their change in vision, such patients do not perceive diplopia, due to a suppression scotoma in the nondominant eye that developed during childhood. However, when there is a change in vision in the dominant eye, fixation may switch to the nondominant eye, effectively removing the suppression scotoma, causing new-onset diplopia without a change in the strabismic angle. To help illustrate this phenomenon, consider the following case. A 66-year-old man reported the onset of diplopia immediately after cataract surgery in his left eye. Medical history was unremarkable, but his ophthalmic history was significant for childhood strabismus and amblyopia. He recalled patching his right eye, as a child, but vision in his left eye was always somewhat “weaker.” Preoperatively, his best-corrected visual acuity was 20/40, right eye and 20/60, left eye. His manifest refraction was +2.50 sphere in each eye. Slit-lamp examination revealed nuclear sclerotic cataracts, left greater than the right. He had a 6 prism diopter left esotropia that was comitant in all directions. He had never noticed diplopia. After uneventful left cataract surgery, the patient began to note binocular horizontal diplopia. His visual acuity postoperatively was 20/40, right eye, and 20/25, left eye. On motility examination, he had full ductions, and a comitant 6 prism diopter esotropia; however, his left eye was now fixating, and he had a manifest right esotropia. The differential diagnosis for this patient’s new onset of diplopia after cataract surgery included myotoxicity from a retrobulbar block, change in strabismic angle, preexisting diplopia that was masked by the diminished vision due to a cataract in his left eye, central disruption of fusion, anisophoria, and fixation switch diplopia. The most likely diagnosis was fixation switch diplopia because the patient did not have a change in his angle of strabismus, there was no restriction in his motility to indicate anesthetic myotoxicity, and his fixation was switched from his dominant right eye to the nondominant left eye due to an improvement in the visual acuity of the left eye. In addition, since he was able to fuse with the prism, central fusion disruption and optical aberrations were much less likely. A decompensation of a previous monofixation syndrome was considered, but unlikely given the small, unchanged esotropia (2). Following successful right cataract surgery (acuity: 20/20), the patient’s fixation switched back to the right eye, and his diplopia was eliminated. Other common scenarios in which fixation switch diplopia occurs include the following: 1) the development of myopia in a previously preferred eye in patients with mild contralateral amblyopia, 2) induced “monovision” either by optical or refractive surgical means, and 3) when patients with mild amblyopia receive an unbalanced refraction that leads to fixation with their nondominant eye (3). In the largest study of patients with fixation switch diplopia, Kushner (3) reviewed the records of 16 patients

title: Persistent diplopia associated with strabismus surgery.
abstract: The primary therapeutic goal for patients with binocular vision problems is comfortable, single, clear, normal binocular vision at all distances and directions of gaze. Strabismus surgery is frequently used to assist in achieving this therapeutic goal. Strabismus surgery is also used for those patients who cannot achieve single normal binocular vision but who have a cosmetically noticeable ocular deviation. However, one of the complications of cosmetic strabismus surgery is persistent diplopia. This possibility must be considered seriously before any cosmetic strabismus surgery is performed. The purpose of this paper is to present a case report of a patient who had diplopia after cosmetic strabismus surgery to emphasize the need for careful consideration of the possibility of persistent diplopia after cosmetic strabismus surgery and how to avoid it.

title: Botulinum toxin injection for postoperative diplopia testing in adult strabismus.
abstract: To investigate the use of botulinum toxin type A in identifying adult patients with constant strabismus who are at high risk of developing intractable diplopia after surgery.



A retrospective review of adult patients with constant horizontal strabismus who had botulinum toxin injection to evaluate their risk of postoperative diplopia. These patients reported diplopia when prisms were used to neutralize the deviation.



One hundred ninety-five adults were studied; their mean age was 40.3 +/- 14 years (range, 16 to 73 years). One hundred thirty-three (68%) had botulinum toxin injected into a lateral rectus muscle; 62 (32%) had injections in a medial rectus muscle. Only 14 (7%) developed diplopia; 9 (4.6%) of these had troublesome diplopia but 5 (2.6%) could cope with the double vision and elected to have surgery. Surgical correction was recommended to the remaining 181 (93%) who did not experience diplopia. Complications of botulinum toxin injection were ptosis (10 patients, 5.1%) and superior oblique muscle weakness (3 patients, 1.5%). Twenty-six patients (13.3%) had a poor response to the first injection and required a second injection with a double dose. Surgery did not result in intractable diplopia after 6 weeks in any patient with a negative botulinum toxin diplopia test.



Botulinum toxin is a useful diagnostic tool for identifying patients with a low risk or no risk of postoperative diplopia despite a positive prism diplopia test.

title: Management of diplopia limited to down gaze.
abstract: To evaluate the usefulness of various optical and surgical treatment modalities in the treatment of patients who were symptom free in the primary position of gaze yet had symptomatic diplopia in the reading position (down gaze at near).  A retrospective chart review was conducted to identify all patients with presbyopia I have treated who were symptom free in the primary position but had diplopia in down gaze associated with vertically incomitant strabismus. Of 51 patients identified, 32 were symptomatic in down gaze due to a hypertropia associated with a unilateral inferior rectus muscle underaction. Twenty-two of these patients had previously undergone recession of the affected inferior rectus muscle for treatment of thyroid eye disease; four patients, for correction of entrapment secondary to blow-out orbital fracture; and four patients, for treatment of superior oblique muscle palsy. Two patients had undergone prior surgery for superior oblique myokymia. Eight patients had horizontal diplopia associated with anApattern, and eight patients had horizontal diplopia associated with aVpattern. Three patients had vertical and horizontal diplopia after partial recovery from third-nerve palsy.  The treatment modalities were varied and individualized. Treatment consisted of optical management (20 patients), surgical management (21 patients), or a combination of both (10 patients). These treatment modalities resulted in comfortable single binocular vision for reading in 41 of the 51 patients. Successful optical treatment consisted of Fresnel prisms (four patients), slab-off prisms (two patients), single-vision readers (seven patients), switch to nonprogressive bifocal lenses (three patients), and a high bifocal segment (16 patients). Successful surgical modalities included posterior fixation of the contralateral inferior rectus muscle (10 patients), surgery forA- orV-pattern strabismus (five patients), or bilateral inferior rectus muscle recession (six patients).  Diplopia in the reading position frequently can be alleviated with a systematic approach that includes both optical and surgical modalities.

title: Superior oblique paralysis. A review of 270 cases.
abstract: In 270 patients with superior oblique paralyses treated between 1973 and 1984, congenital and traumatic causes were most frequent, and one fourth of all traumatic cases had bilateral involvement. Among the diagnostic features distinguishing bilateral from unilateral paralysis were a right hypertropia in left gaze and left hypertropia in right gaze, and a positive Bielschowsky test on tilting the head toward either shoulder. However, absence of either sign did not exclude bilateral paralysis. Large excyclotropia and a V-pattern esotropia are suggestive of but not diagnostic for bilateral paralysis. Complaints about cyclotropia are limited to acquired paralysis. Cyclotropia in the normal eye, head tilt toward the involved side, or absence of any abnormal head posture limits the diagnostic value of these associated signs. Overshoot of the contralateral superior oblique occurred in 19% of the patients and is thought to be caused by contracture of the ipsilateral superior rectus muscle. Surgical treatment in 112 patients resulted in an 85% cure rate with an average of 1.45 operations per patient.

title: Clinical characteristics of cyclodeviation
abstract: PurposeTo retrospectively evaluate the incidence of cyclodeviation among patients with diplopia and analyse the causative diseases and clinical manifestations of cyclodeviation.MethodsThe medical records of 266 consecutive patients of 15 years of age or older presenting with diplopia, who had undergone the Lancaster red–green test (LRGT) from January 2001 to December 2002, were retrospectively reviewed. The presence of cyclodeviation on LRGT, predisposing conditions, causative diseases, and clinical manifestations of cyclotropia were analysed. Cyclodeviation on the LRGT were compared with those from the Maddox double-rod test (MDRT) and fundus photography. total of 63 (24%) out of 266 patients exhibited cyclodeviation on LRGT. Eight out of 63 patients with cyclodeviation on the LRGT complained of torsional diplopia. Superior oblique palsy (SOP) was the most common causative disease (42 patients), followed by skew deviation (six) and thyroid orbitopathy (three). Excyclodeviation was found in 57 patients and incyclodeviation in four patients on the LRGT. The spontaneous recovery rate was 83% in patients of vascular origin and 17% of traumatic origin. Cyclodeviation with the MDRT and fundus photography showed good correlation with those obtained from the LRGT. There was no association of the amount of cyclotropia with the presence of torsional diplopia as well as with its recovery.ConclusionIn spite of the rare complaint of torsional diplopia, 24% of the patients with diplopia showed cyclodeviation on the LRGT. SOP was the most common causative disease. Most of the patients with cyclodeviation of a vascular origin showed spontaneous improvement.

title: Prescribing cylinders: the problem of distortion.
abstract: Astigmatic spectacle corrections produce distortion of retinal images. Under binocular conditions, small amounts of monocular distortion may significantly alter the sense of spatial localization, producing symptomatic binocular distortion. From examination of the nature and sources of monocular distortion, a rational basis may be developed for methods to minimize distortion when necessary. Adaptation to distortion occurs both by interpretive and physiological mechanisms, with the physiological mechanism appearing to be a type of rotational anomalous retinal correspondence. Through better knowledge of distortion and adaptive mechanisms, a revised set of practical guidelines for prescribing cylinders is presented.

title: Diplopia secondary to aniseikonia associated with macular disease.
abstract: To provide an explanation for diplopia and the inability to fuse in some patients with macular disease.



We identified 7 patients from our practices who had binocular diplopia concurrent with epiretinal membranes or vitreomacular traction. A review of the medical records of all patients was performed. In addition to complete ophthalmologic and orthoptic examinations, evaluation of aniseikonia using the Awaya New Aniseikonia Tests (Handaya Co Ltd, Tokyo, Japan) was performed on all patients.



All patients were referred for troublesome diplopia. Six of the patients had epiretinal membranes and 1 had vitreomacular traction. All 7 patients had aniseikonia, ranging from 5% to 18%. In 5 of the patients the image in the involved eye was larger, and in the other 2 patients it was smaller than in the fellow eye. All patients had concomitant small-angle strabismus and at least initially did not fuse when the deviation was offset with a prism. Response to optical management and retinal surgery was variable.



Aniseikonia caused by separation or compression of photoreceptors can be a contributing factor to the existence of diplopia and the inability to fuse in patients with macular disease. Concomitant small-angle strabismus and the inability to fuse with prisms may lead the clinician to the incorrect diagnosis of central disruption of fusion. Surgical intervention does not necessarily improve the aniseikonia.

title: Simulated torsional disparity disrupts horizontal fusion and stereopsis.
abstract: To investigate how increasing torsional disparity affects clinical measures of the quality of binocular single vision.



Synoptophore targets were adjusted to present varying degrees of torsional disparity (relative to the fusion-free rest position of the eyes) such as might be observed in a patient with excyclotropia. This disparity was increased in 2 degrees increments up to 10 degrees in 21 normal subjects. The fusional divergence and convergence amplitudes and random-dot stereoacuity were measured at each level of torsional disparity.



Horizontal fusional vergence was not significantly altered from the baseline measures at 2 degrees and 4 degrees of torsional disparity. However, both the divergence and the convergence amplitudes declined and were significantly different than the baseline measures at 6 degrees . A similar decline in the random-dot stereoacuity measurements was evident. Fine levels of stereopsis were decidedly affected at greater than 4 degrees of torsional disparity, while more gross levels were similarly affected beyond 6 degrees .



Although human binocular vision can demonstrate the sensory capacity for cyclofusion beyond 10 degrees , torsional disparity of 6 degrees or more significantly degrades horizontal fusional vergence and stereopsis. Torsion in excess of this degree might therefore be a barrier to asymptomatic and comfortable binocular single vision and may require appropriate attention in the planning of more successful surgery for superior oblique palsy and cyclovertical incomitant strabismus.

title: Exotropia associated with defective accommodation.
abstract: Despite the close association of convergence and accommodation, accommodative dysfunction is not often associated etiologically with exotropia. We studied 13 adolescent and young adults having intermittent exotropia and severely reduced accommodative function. Most patients had a prolonged history of visual symptoms that had not responded to therapy in the past. Clinical testing indicated that the patients had severely reduced amplitudes of accommodation and difficulty sustaining accommodation. Exotropia was manifest when the accommodative response was inadequate; relative orthophoria existed when the accommodative response was adequate. Treatment of the accommodative defect as well as the strabismus was successful for some patients. We recommend careful evaluation of accommodation for adolescent and young adults with exotropia to rule out an accommodative defect as a contributing cause.

title: ACCOMMODATIVE DISFACILITY PRESENTING AS INTERMITTENT EXOTROPIA
abstract: Accommodative disfacility and intermittent exotropia are two common clinically‐observed ocular abnormalities. However, records of individual system dynamics arc rare and mechanisms for possible interactive effects between the accommodation and the vergence system remain obscure in cases of system dysfunction. We present objective, quantitative, static and dynamic records of accommodation, vergence and related system responses in a symptomatic patient having accommodation disfacility and intermittent exotropia and propose that these two conditions worked in a pathogenic symbiotic manner.

title: Accommodative spasm: a study of 17 cases.
abstract: Accommodative spasm (AS) is rarely reported in the literature. We studied 17 patients with accommodative spasm. Most patients were clinically emmetropic. Ten patients also manifested a spasm of the near reflex (SNR). The probable etiology of the accommodative disorder for most patients was psychogenic as revealed by case histories and visual field analysis. Treatment consisted primarily of plus reading lenses and, in some instances, orthoptic training. Some patients also underwent psychological counseling. Follow-up ranged from 2 months to 30 months. Although visual symptoms improved for most patients, only four patients had complete resolution of the spasm.

title: Accommodative spasm with bilateral vision loss due to untreated intermittent exotropia in an adult.
abstract: Intermittent exotropia (IXT) is an exodeviation intermittently controlled by fusional mechanisms. Patients with IXT may present with asthenopic symptoms, blurred vision, headaches, diplopia or visual confusion and reading difficulties; especially after prolonged periods of near work.



To report the presentation and management of a young adult with intractable accommodative spasm secondary to long standing intermittent exotropia.



The patient was found to have bilateral accommodative spasm with high pseudomyopia and severe impairment of vision. There was a tendency for recurrence with discontinuation of cycloplegics.



A total relief of symptoms was noticed after strabismus surgery was undertaken for the exotropia. A detailed orthoptic evaluation with emphasis on recognizing accommodative spasm as an unusual presentation of IXT, could aid in appropriate diagnosis and treatment of such cases.

title: Decreased accommodation during decompensation of distance exotropia
abstract: Disparity cues can be a major drive to accommodation via the convergence accommodation to convergence (CA/C) linkage, but, on decompensation of exotropia, disparity cues are extinguished by suppression so this drive is lost. This study investigated accommodation and vergence responses to disparity, blur and proximal cues in a group of distance exotropes aged between 4 and 11 years both during decompensation and when exotropic.  19 participants with distance exotropia were tested using a PlusoptiXSO4 photo refractor set in a remote haploscopic device that assessed simultaneous vergence and accommodation to a range of targets incorporating different combinations of blur, disparity and proximal cues at four fixation distances between 2 m and 33 cm. Responses on decompensation were compared with those from the same children when their deviation was controlled.  Manifest exotropia was more common in the more impoverished cue conditions. When decompensated for near, mean accommodation gain for the all-cue (naturalistic) target was significantly reduced (p<0.0001), with resultant mean under-accommodation of 2.33 D at 33 cm. The profile of near cues usage changed after decompensation, with blur and proximity driving residual responses, but these remaining cues did not compensate for loss of accommodation caused by the removal of disparity.  Accommodation often reduces on decompensation of distance exotropia as the drive from convergence is extinguished, providing a further reason to try to prevent decompensation for near.

title: Evidence that convergence rather than accommodation controls intermittent distance exotropia
abstract: This study considered whether vergence drives accommodation or accommodation drives vergence during the control of distance exotropia for near fixation. High accommodative convergence to accommodation (AC/A) ratios are often used to explain this control, but the role of convergence to drive accommodation (the CA/C relationship) is rarely considered. Atypical CA/C characteristics could equally, or better, explain common clinical findings.

title: Where the Wild Things are: When Esotropia Misbehaves
abstract: Esotropia is the most common form of strabismus seen in clinic. Accommodation is known to be an important precipitating factor, and its management is usually not complex. In this paper, I have reviewed a dozen circumstances in which the presentation was complicated. For some patients, the cause of fleeting symptoms was elusive and had to be determined through careful sensory and motor testing. In others, the presentation was indicative of serious underlying pathology that warranted further investigation. Lastly, restrictive conditions may be erroneously thought to be neurological, and some of these are also discussed. The patients presented include the following problems: fixation switch diplopia, consecutive esotropia unmasking superior oblique palsy, over-corrected myopia, acute nonaccommodative esotropia, comitant esotropia with underlying cerebellar tumor, sixth nerve palsy due to pontine tumor or cavernous pathology, and thyroid strabismus mimicking sixth nerve palsy.

title: Spasm of the Near Reflex Mimicking Deteriorating Accommodative Esotropia
abstract: To describe a patient with accommodative esotropia who developed spasm of the near reflex. Case report A 6-year-old girl with a history of successfully treated refractive, accommodative esotropia suddenly developed spasm of the near reflex after the death of a relative. The condition resolved after 2 months.  Spasm of the near reflex should be considered in children with accommodative esotropia who seem to deteriorate and become esotropic once again while wearing their hyperopic glasses.

title: Acute Adult Onset Comitant Esotropia Associated with Accommodative Spasm
abstract: Acute onset comitant esotropia associated with spasm of accommodation in children and adults is a rare clinical condition. When occurring with pupillary miosis and restricted ocular motility, it is referred to as “spasm of near reflex” (SNR) and may require neurological investigation. The natural history of SNR depends on its etiology. There is little information in the literature regarding the long-term follow-up of SNR and the stability of visual signs and symptoms following cessation of treatment. We report a case of SNR in an otherwise healthy young male, and discuss the presentation, clinical investigations, management, response to treatment, and 1-year follow-up.  A 23-year-old male patient reported to the clinic with sudden onset of blurred vision, inward deviation of the eyes, and binocular diplopia. On examination, he was diagnosed to have acute onset esotropia resulting from SNR. He was treated with cycloplegic medications and vision therapy. The condition resolved following 1 year and there has been no recurrence.  Acute adult onset esotropia occurring with accommodative spasm responds favorably to cycloplegic medications but may need a longer course of treatment for successful resolution and stability.

title: Unusual Presentation of Spasm of Near Reflex Mimicking Large-Angle Acute Acquired Comitant Esotropia
abstract: We report the case of an 11-year-old boy who presented with sudden esotropia, binocular diplopia, and blurred vision. The patient was neurologically normal. He had a large, constant, comitant, alternating esotropia associated with minimal accommodative spasm. Ocular motility and pupillary reactions were normal. He was diagnosed to have spasm of the near reflex presenting as acute onset of esotropia. The esotropia was persistent despite treatment and eventually resolved with prolonged cycloplegic therapy. This unusual case illustrates that spasm of the near reflex can have unique and variable presentations. Spasm of the near reflex needs to be considered in the differential diagnosis of every case of acute, acquired, comitant esotropia. This is the first case of spasm of the near reflex where persistent esotropia is reported in the absence of any neurological disorder.

title: Spasm of the near reflex: a spectrum of anomalies.
abstract: Spasm of the near reflex has been characterized as the variable appearance of pseudomyopia, convergent strabismus and miosis. These characteristics may appear together or separately. In addition, abnormalities of accommodation may appear not only as pseudomyopia, but may also be manifest in cases with significant hypermetropia in which the patient is unable to relax accommodation even when plus lenses are used. The intent of this review is to identify the various clinical presentations of anomalies of the entire near reflex as well as the component parts. The relationship to functional and organic disorders are discussed as well as the related neuroanatomy. We suggest that one may more readily understand the clinical manifestations as a spectrum of anomalies of the near reflex rather than a multitude of disconnected entities.

title: Accommodative spasm might influence surgical planning and outcomes in acute acquired distance esotropia in myopia.
abstract: Acute acquired distance esotropia (AADE) is a poorly understood moderate-angle strabismus, affecting young adult myopes and determining bothersome diplopia. Symptoms can be intermittent in the early stages, becoming constant in long-lasting disease. Symptomatic therapy includes prism correction, while surgery is the only curative treatment. However, the latter is affected by high rate of symptoms recurrence with the frequent need for reoperation.



We hypothesize that AADE could be caused by the increase of the accommodative demand, often secondary to a myopic overcorrection. This condition could determine an increase in induced hyperopia at near, dominated by an excess of accommodation and therefore of convergence. The latter cannot be relaxed at distance and diplopia develops. We speculate that early-stage AADE could be successfully treated by cycloplegic eye drops slowly tapered within three months. On the other hand, surgery remains the only option in long-lasting AADE. In these cases, we propose a new pre-operative assessment of esotropia by asking the patient to fix alternatively a stimulus at near and at distance in order to stimulate the accommodative convergence. This technique allows to unmask the total amount of the angle of deviation and to plan a wider bilateral medial rectus muscle recession avoiding long-term residual esotropia.



Currently, AADE curative therapy is surgical regardless of onset time but it is usually affected by poor outcomes. If our hypothesis was to be confirmed, pharmacological treatment could solve early-stage AADE, avoiding any surgery. Furthermore, a wide bilateral medial rectus muscle recession, quantified on the basis of the above mentioned test for measuring the total amount of the strabismus angle, could improve outcomes eliminating the need for reoperation in long-lasting AADE.

title: Misdiagnosis of spasm of the near reflex
abstract: A bilateral sixth nerve palsy portends serious disease of the central nervous system and precipitates extensive patient studies. Spasm of the near reflex, characterized by intermittent convergence, accommodation, and miosis, is a functional disturbance. Five patients with hysterical spasm of the near reflex erroneously diagnosed as a bilateral sixth nerve palsy are reported. The pupillary sign, intense miosis on attempted lateral gaze, is emphasized as an important clue to the correct diagnosis. Despite extensive investigation, no disease of the central nervous system was found. Neurotic or hysterical features were evident in every patient.

title: Spasm of the near reflex associated with organic disease.
abstract: Spasm of the near reflex is characterized by transient attacks of convergence, accommodation, and miosis. It is usually observed in young individuals and considered functional. We studied seven patients with spasm of the near reflex who had associated neurologic disorders or head trauma. Two patients had posterior fossa abnormalities (cerebellar tumor, Arnold-Chiari malformation), two patients had pituitary tumors, one patient had a vestibulopathy, and two patients had a history of antecedent head trauma.

title: Spasm of the near reflex. Treatment with botulinum toxin
abstract: A 38-year-old female with diplopia and esotropia, with limitation of ocular abduction in both eyes, with full abduction after doll's head rotation also being observed. She was diagnosed with spasm of the near reflex. Treatment with injections of botulinum toxin in both medial rectus has temporally resolved the convergence spasm.  Near reflex spasm is characterized as miosis, pseudomyopia, and convergent strabismus that lead to diplopia, blurred vision, headache, and variable, progressive, and intermittent esotropia. As the spasm worsens there will be limited ocular versions and ductions simulating a sixth nerve palsy. Botulinum toxin may be effective in some cases.

title: Nonsurgical Management of Diplopia After Retinal Surgery
abstract: For those who manage strabismus in adults, the patient with diplopia following retinal surgery presents a challenge. Mechanical and sensory factors may combine to preclude single binocular vision, and neutralizing the patient's strabismus may not be sufficient to permit resolution of their diplopia. This paper reviews the issues involved and discusses some potential solutions.

title: Management of Binocular Diplopia Due to Maculopathy with Combined Bangerter Filter and Fresnel Prism
abstract: To describe treatment of binocular diplopia due to maculopathy with a combination of Bangerter foil and Fresnel prism.  A protocol for prescribing a combination of Bangerter foil and Fresnel prism is described. A series of three patients in whom a Bangerter foil or prism alone were ineffective for binocular diplopia due to maculopathy, along with a detailed case report of one of these patients, illustrates how a combination of both were used to treat the diplopia.  Fogging is presumed to relieve binocular diplopia due to maculopathy by inducing a functional central scotoma in the affected eye. In some patients, prism correction is needed in addition to a Bangerter foil to eliminate diplopia, possibly by impoving superimposition of the scotoma in the affected eye and the fovea of the sound eye.

title: Aniseikonia associated with epiretinal membranes
abstract: To determine whether the computerised version of the new aniseikonia test (NAT) is a valid, reliable method to measure aniseikonia and establish whether aniseikonia occurs in patients with epiretinal membranes (ERM) with preserved good visual acuity.  With a computerised version of the NAT, horizontal and vertical aniseikonia was measured in 16 individuals (mean 47 (SD 16.46) years) with no ocular history and 14 patients (mean 67.7 (14.36) years) with ERM. Test validity was evaluated by inducing aniseikonia with size lenses. Test reliability was assessed by the test-retest method.  In normal individuals, the mean percentage (SD) aniseikonia was −0.24% (0.71) horizontal and 0% (0.59) vertical. Validity studies revealed mean (SD) 0.990 (0.005) horizontal and 0.991 (0.004) vertical correlation coefficients, 0.985 (0.111) horizontal and 0.989 (0.102) vertical slope. Repeatability coefficients were 1.04 horizontal and 0.88 vertical. Aniseikonia in patients with ERM ranged from 4% to 14%. Eight patients showed 2% or more size difference between horizontal and vertical meridians.  The aniseikonia test used in this study can be considered a simple, fast, valid and reliable method to measure the difference in image size perceived by each eye. Aniseikonia does occur in symptomatic patients with ERM. The effect of ERM on image size is heterogeneous across the retinal area affected.

title: Retinally-induced aniseikonia.
abstract: To show that retinally-induced aniseikonia may vary as a function of visual field angle (i.e., field-dependent aniseikonia), how this could be explained, and what implications this has for managing the aniseikonia.



Observational case series.



Self-administration using software that can be assumed the predecessor of the Aniseikonia Inspector version 2. Aniseikonia was tested in the vertical nd horizontal direction. In each direction aniseikonia was tested for visual field angles of 0.5 to 8 degrees.



Three patients with different retinal conditions: an epiretinal membrane (ERM), a retinal detachment (RD), and a retinoschisis.



All patients had field- dependent aniseikonia, with aniseikonia variations of up to 20% over the measured visual field. The aniseikonia for the ERM patient was similar in the vertical and horizontal direction, while this was not the case for the RD patient and the retinoschisis patient. The retinoschisis patient even had negative aniseikonia in one direction and positive aniseikonia in the other direction.



When reporting the aniseikonia of patients with retinal conditions, one cannot speak of 'the' aniseikonia(i.e., a single value or a single value for each direction), because it is most likely field-dependent. It is also important to use a test that only measures static aniseikonia (direct comparison tests with long viewing times may be less suitable). Correction of field- dependent aniseikonia is relatively difficult, because an optical correction is field-independent. Nevertheless, optically correcting the aniseikonia for part of the visual filed often improves the vision comfort considerably. If necessary, an optical correction could be augmented with a unilateral partial transparency occlusion or a unilateral partial field occlusion for more vision comfort.

title: Retinally Induced Aniseikonia: A Case Series
abstract: To report the clinical findings for patients with binocular vision difficulties attributed to retinally induced aniseikonia.  Clinical records of patients referred to the author and diagnosed with retinally induced aniseikonia from 2006 to 2012 were retrospectively reviewed.  Twelve patients with retinally induced aniseikonia attributed to epiretinal membrane, retinal detachment surgical repair, or age-related macular degeneration are reported. Eleven patients were male. The age range was 44 to 76 years. Diplopia occurred in 10 patients, and prism lenses were prescribed for seven patients by their referring practitioner. The amount of aniseikonia measured using either the computerized Aniseikonia Inspector (visual field angle, ∼ 14.5 degrees) or the New Aniseikonia Test (visual field angle, ∼ 5.7 degrees) ranged from 1.7 to 11.3% and from 1.5 to 13.3% in the vertical and horizontal meridians, respectively. At other visual field angles, the amount of aniseikonia might have been different. Five patients perceived macropsia and seven patients perceived micropsia in the affected eye. Seven patients had measurable stereopsis. Use of Bangerter filters was the most frequent treatment modality. Detailed case reports on three patients are included.  Retinally induced aniseikonia is an increasingly important cause of binocular vision symptoms in the aging population. Long-term studies on its incidence, clinical course, and effect of treatment are needed.

title: Field-dependent aniseikonia associated with an epiretinal membrane a case study.
abstract: Aniseikonia is a binocular anomaly in which the two eyes perceive images of different sizes and/or shapes. It is usually assumed to be constant as a function of visual field angle (VFA) (i.e., angular distance from the line of sight). This is correct for optically induced aniseikonia, such as the aniseikonia that is associated with anisometropia and probably also pseudophakia. The purpose of this article is to show that if the aniseikonia is of retinal origin, then the aniseikonia may no longer be constant as a function of VFA (i.e., field-dependent aniseikonia).



Case report, with the patient having a unilateral epiretinal membrane.



The aniseikonia was measured in vertical and horizontal directions with a customized version of the Aniseikonia Inspector software. The VFA was made variable by changing the dimensions of the comparison targets in the direct comparison procedure.



Aniseikonia as a function of VFA.



The patient exhibited good repeatable aniseikonia, ranging from 23% to 2.5% for VFAs ranging from 0.36 degrees to 5.7 degrees . Higher angles had lower aniseikonia. A control subject did not show this field-dependent aniseikonia.



Aniseikonia may vary with VFA due to a retinal cause such as an epiretinal membrane. The problem with field-dependent aniseikonia is that it cannot be corrected fully with conventional optics, which exhibit an approximately constant magnification as a function of VFA. Nevertheless, by correcting 5% to 10% aniseikonia, which showed up in the VFA measurement range at 2 degrees to 3 degrees , our patient had improved visual comfort, especially for reading.

title: RESTORATION OF RETINALLY INDUCED ANISEIKONIA IN PATIENTS WITH EPIRETINAL MEMBRANE AFTER EARLY VITRECTOMY
abstract: To evaluate changes in aniseikonia in patients with unilateral epiretinal membrane after surgery.  This prospective study included 24 patients with unilateral idiopathic epiretinal membrane who underwent vitrectomy. Best-corrected visual acuity and aniseikonia were measured using the Aniseikonia Inspector 3 (Optical Diagnostics, Culemborg, The Netherlands) preoperatively and 6 months postoperatively. Aniseikonia was measured in vertical and horizontal directions.  Mean age at surgery was 64.2 ± 9.3 years, and mean symptom duration was 12.9 ± 11.4 months. Mean changes in aniseikonia after surgery were 41.0 ± 31.4% reduction in the vertical direction and 41.6 ± 30.8% reduction in the horizontal direction (both P < 0.001). The remaining aniseikonia after surgery correlated with symptom duration (r = 0.565, P = 0.006, and r = 0.812, P < 0.001, for vertical and horizontal directions, respectively). The good preoperative best-corrected visual acuity group showed better improvement of aniseikonia than did the poor preoperative group (P = 0.046 and P = 0.025 for vertical and horizontal directions, respectively).  Greater improvement of aniseikonia after epiretinal membrane peeling was achieved in patients with better preoperative best-corrected visual acuity and shorter symptom durations. Early vitrectomy helped to reduce aniseikonia in patients with epiretinal membrane.

title: Partial Correction of Irregular Aniseikonia Secondary to Retinal Traction
abstract: This case report presents the management of symptomatic retinally induced aniseikonia and a short review of the literature pertaining to two clinical tests used in the measurement and management of aniseikonia. The clinician is also provided a review of how to design eikonic lenses.  A 30-year-old white male presented with symptoms of perceived image size difference after scleral buckle repair for retinal detachment in the right eye. Three measures of aniseikonia resulted in markedly different values, but all indicated larger perceived left eye image. Stereopsis was measured before and after placing an afocal magnifying lens over the right eye. Stereopsis improved immediately upon placement of the afocal lens, with further improvement after 20 minutes, and stereopsis decreased upon removal. The patient reported improved visual comfort for near work with the afocal lens. Eikonic glasses were designed, and the patient reported improved comfort for near work that has remained for over 1 year of wear. Studies evaluating the validity and reliability of the New Aniseikonia Test and the Aniseikonia Inspector are reviewed. Most studies report that induced aniseikonia is underestimated. This case report illustrates that despite the problem with underestimation, these tests are useful clinical tools to identify whether aniseikonia exists and which eye has the larger perceived image. Results can be used as a starting point when making clinical decisions about managing aniseikonia. The Aniseikonia Inspector also assists in the design of eikonic glasses.  Even when aniseikonia is substantial, variable in magnitude, and irregular due to retinal disease, reducing the overall aniseikonia can improve binocularity and patient's comfort noticeably for the long term. The underestimation of induced aniseikonia in clinical tests does not preclude their use as a tool in the management of symptomatic aniseikonia.