bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of the Reliability of the Nidek MK-2000 Microkeratome for Laser in situ Keratomileusis
Authors: Naripthaphan Pichit , Vongthongsri Anun
Published: April 2021

ABSTRACT

PURPOSE: To evaluate the performance of the Nidek MK-2000 microkeratome in eorneal flap creation for laser in situ keratomileusis (LASIK) in Asian eyes and the simplicity of its use for the beginner.

METHODS: A prospective study of 200 Asian eyes was performed. The corneal flaps were created using the Nidek MK-2000 microkeratome 130-µm and 160-µm thickness plates with 8.5- and 9.5-mm suction rings. Ease of obtaining suction was evaluated and measurements were done for flap thickness, flap diameter, hinge size, and hinge-to-center-of-pupil distance.

RESULTS: Subjectively, even in small eyes, the procedure of obtaining the required suction and creating a good flap was easy and reliable with the Nidek MK-2000 microkeratome. Average flap thickness was 120.52 ± 16.49 µm (range, 84 to 162 µm) for the 130-µm thickness plate with the 8.5-mm suction ring. Mean flap diameter was 9.16 ± 0.43 mm, mean hinge size was 4.96 ± 0.36 mm, and mean hinge-tocenter-of-pupil distance was 4.16 ± 0.28 mm. With the 9.5-mm suction ring, mean flap thickness was 122.06 ± 18.54 µm (range, 84 to 149 µm), mean flap diameter was 9.85 * 0.35 mm, mean hinge size was 5.28 ± 0.36 mm, and mean hinge-to-center-of-pupil distance was 4.49 ± 0.27 mm. For the 160-µm plate with a 8.5-mm suction ring, the flap thickness was 172.71 ± 27.49 µm (range, 121 to 203 µm), flap diameter was 9.13 + 0.37 mm, mean hinge size was 5.02 ± 0.29 mm and mean hinge-to-center-of-pupil distance was 4.21 ± 0.29 mm. There were no complications of corneal flap creation.

CONCLUSION: The Nidek MK-2000 microkeratome was effective, safe, and reliable, even in small eyes. [J Refract Surg 2001;17(suppl): S255-S258]
Morphology of the Stromal Surface and Endothelium Using Two Different Microkeratomes
Authors: Frueh Beatrice E , Eggli Peter , Böhnke Matthias
Published: April 2021

ABSTRACT

PURPOSE: To compare stromal surface and endothelial morphology after keratectomies and after laser in situ keratomileusis (LASIK), using two different microkeratomes.

METHODS: Keratectomies (lGO-µm and 400-µm) were performed on 82 enucleated porcine eyes using the Chiron Automated Corneal Shaper (52 eyes) and the Microtech Turbokeratome (30 eyes). LASIK procedures of -9.00 D, -27.00 D, and -36.00 D were performed with a Schwind excimer laser. The corneas were immediately fixed in glutaraldehyde or stained with alizarin red and trypan. Scanning electron microscopy was then performed.

RESULTS: All keratectomies performed with the Chiron microkeratome displayed a relatively smooth surface. The quality of the keratectomies with the manually advanced Microtech microkeratome was variable, with a high incidence (4 of 9) of incomplete cuts and irregular surfaces. In the eyes in which the stromal laser ablation was performed, a thin layer of condensed stroma (pseudomembrane formation) was seen. Vital staining did not indicate endothelial damage.

CONCLUSIONS: The surface morphology was unacceptable for one of the microkeratomes tested. Keratectomies of 160 to 400 µm and LASIK up to -36.00 D did not acutely alter endothelial morphology in porcine eyes. [J Refract Surg 2001;17:428-432]
Diffuse Lamellar Keratitis Associated With Recurrent Corneal Erosions After Laser in situ Keratomileusis
Authors: Harrison Devin A , Periman Laura M
Published: April 2021

ABSTRACT

PURPOSE: Diffuse lamellar keratitis (DLK) is marked by the presence of diffuse or multifocal infiltrates confined to the laser in situ keratomileusis (LASDX) interface. These infiltrates are culturenegative, and the etiology is thought to be noninfectious. Most cases of DLK occur within the first week or two following surgery.

METHODS: We describe one case of diffuse lamellar keratitis that occurred 3 months after LASLK. The patient developed a spontaneous corneal erosion in one eye. Over the next 2 days while the erosion was being treated, there was rapid development of DLK. Slit-lamp biomicroscopy and in vivo scanning slit confocal microscopy were performed. The patient was treated with intensive topical corticosteroids.

RESULTS: Scanning slit confocal microscopy revealed numerous, highly-reflective round bodies consistent with a polymorphonuclear infiltrate located at the flap interface. Treatment with topical 1.0% prednisolone acetate was instituted, with rapid improvement in patient symptoms, visual acuity, and slit-lamp biomicroscopy.

CONCLUSIONS: Diffuse lamellar keratitis may occur months after LASlK as a result of a spontaneous recurrent corneal epithelial erosion. [J Refract Surg 2001;17:463-465]
Phototherapeutic Keratectomy in Patients With Recurrent Corneal Epithelial Erosions
Authors: Rashad Khaled M , Hussein Hussein A , El-Samadouny M Alaa , El-Baha Samir , Farouk Hisham
Published: April 2021

ABSTRACT

PURPOSE: To evaluate the outcome of phototherapeutic keratectomy (PTK) in the management of recurrent corneal erosions, refractory to other forms of treatment.

METHODS: Phototherapeutic keratectomy was performed on 43 eyes of 41 patients with recurrent corneal erosions. The corneal epithelium was debrided, and laser ablation was performed to a depth of 6 µm with an ablation zone of 7 to 9 mm, using the Technolas Keracor 117C PlanoScan excimer laser. Follow-up time was 12 to 48 months (mean, 23.3 ±9.1 mo).

RESULTS: After PTK, patients were free of symptoms in 31 eyes (72.1%), and eight eyes (18.6%) had occasional mild symptoms of irritation and photophobia upon awakening. Recurrence of painful corneal erosions occurred in four eyes (9.3%). After PTK retreatment, these patients did not report any further episodes and were free of symptoms for 12 to 30 months (mean, 21.0 ± 7.7 mo). The mean spherical equivalent manifest refraction was changed by +0.15 ± 0.39 D in the hyperopic direction at 1 year after PTK. Thirty-three eyes (76.7%) were within ±1 line of preoperative best spectacle-corrected visual acuity (BSCVA). BSCVA was improved by two or more lines in 10 eyes (23.3%). There were no significant complications.

CONCLUSION: Excimer laser PTK with the Technolas Keracor 117C excimer laser was a safe and effective procedure for the treatment of recurrent corneal erosions. Excimer laser PTK can also be useful in improving the visual acuity in these patients. A small percentage of patients may require a second PTK to prevent further episodes of corneal erosions. [J Refract Surg 2000; 17: 511-518]
Two-year Corneal Endothelial Cell Assessment Following INTACS Implantation
Authors: Azar Ramzy G , Holdbrook Mark J , Lemp Michael , Edelhauser Henry F
Published: April 2021

ABSTRACT

PURPOSE: To evaluate the 2-year effects of intrastromal corneal ring segments (INTACS) on the corneal endothelium.

METHODS: Non-contact specular microscopy was performed as a subgroup test in a Phase III clinical trial. Endothelial cell images were collected before surgery and at 6, 12, and 24 months after surgery at the central and peripheral (6 and 10 o'clock) regions. Images were recorded and analyzed later by a central reading center. Cell density, coefficient of variation, and percent hexagonal cells were determined.

RESULTS: There were no clinically significant changes in the endothelial cell structure at 6, 12, and 24 months (102 eyes). There was a gain of 5 cells/mm2 (6 months) and 3 cells/mm2 (12 months) at the central region of the cornea and a loss of 28 cells/mm2 at 24 months. At the 6 o'clock region of the cornea, there was a loss of 0, 24, and 92 cells/mm2 at 6, 12, and 24 months. At the 10 o'clock region of the cornea, there was a loss of 14, 30, and 94 cells/mm2 at 6, 12, and 24 months. INTACS did not statistically affect the central cell density at 6 and 12 months, however, there was a slight loss centrally at 24 months. At 24 months, all corneal regions had a slight decrease in cell density. In all eyes, mean central and peripheral endothelial cell counts remained above 2495 cells/mm2. Coefficient of variation improved and percent hexagonal cells remained unchanged.

CONCLUSION: Endothelial cell density changes at 2 years after INTACS implantation were not clinically significant and endothelial cell remodeling was present. [J Refract Surg 2001;17:542-548J
Keratolysis Following Excimer Laser Phototherapeutic Keratectomy in a Patient With Keratoconus
Authors: Lahners William J , Russell Buddy , Grossniklaus Hans E , Stulting R Doyle
Published: April 2021

ABSTRACT

PURPOSE: We report a case of keratolysis following phototherapeutic keratectomy (PTK) for a subepithelial nodule in a patient with keratoconus.

METHODS: A 29-year-old male with keratoconus who became contact lens intolerant because of a raised subepithelial nodule was treated with excimer laser phototherapeutic keratectomy (PTK).

RESULTS: The epithelium failed to heal postoperatively, and progressive keratolysis led to a central descemetocele by the eighth postoperative day. The patient was managed with a penetrating keratoplasty.

CONCLUSIONS: Excimer laser phototherapeutic keratectomy has been shown to be an effective treatment for subepithelial nodules in patients with keratoconus. Rapidly progressive keratolysis is a potential complication of this procedure. [J Refract Surg 2001;17:555-558]
Dehiscence of Radial Keratotomy Wounds Without Globe Rupture Following Explosion Injury
Authors: Bouchard Charles S , Vaziri Boyd
Published: April 2021

ABSTRACT

PURPOSE: To report a case of explosive trauma to a patient with a history of radial keratotomy (RK), which resulted in multiple wound dehiscences but not globe rupture.

METHODS: A 29-year-old male underwent radial keratotomy 1 year before he sustained facial trauma from a gasoline tank explosion. Corneal abrasions were treated with copious irrigation, topical antibiotics, corticosteroids, and scopolamine. He did not have a ruptured globe in either eye.

RESULTS: The incision sites from radial keratotomy had evidence of anterior dehiscence in both eyes. One month following the injury, the patient had corrected visual acuity of 20/20-1 in the right eye and 20/25+1 in the left eye. At that time, the RK wounds were well healed with minimal irregularity over the incision sites.

CONCLUSION: This case demonstrates the excellent recovery of visual acuity in a patient with a partial thickness traumatic wound rupture 12 months following radial keratotomy. [J Refract Surg 2001;17:561-563]
Wavefront Customized Ablations With the WASCA Asclepion Workstation
Authors: Panagopoulou Sophia I , Pallikaris Ioannis G
Published: April 2021

ABSTRACT

PURPOSE: WASCA (Wavefront Aberration Supported Cornea Ablation) is a method for wavefront-guided ablation. This new method records all existing eye aberrations with the Asclepion Wavefront Aberrometer and calculates the customized pattern for laser correction. We measured the low and high order aberrations of eyes before and after PRK and LASIK, as well as before and after flap creation.

METHODS: The Asclepion Shack-Hartmann aberrometer was used to measure wavefront aberrations. Preoperative and postoperative measurements were made following both PRK and LASIK performed with conventional software, modified Aberration-free Profile (AFA) software, and specially designed WASCA software. Surgery was performed with the Meditec MEL-70 G-scan excimer laser. Additionally, measurements were made before and after flap creation only (10 eyes).

RESULTS: There was a significant difference between preoperative and 1 -month postoperative high order aberrations, with notable increases following conventional PRK and LASIK and less increase following modified AFA PRK and LASIK. Flap creation only changed the higher order aberrations slightly, and caused a shift toward hyperopia. In the eyes that received WASCA correction with PRK or LASIK, at 3 months postoperative the high order aberrations averaged an increase of 1.3 times for PRK and 1.8 times for LASIK. Both the AFA and WASCA treatments demonstrated improved outcomes in comparison to conventional PRK and LASIK.

CONCLUSION: Wavefront mapping of the eye and wavefront-guided ablation with the Asclepion Aberrometer can be used for optimizing the results and fine-tuning visual performance after laser vision correction. WASCA PRK appeared to result in better outcomes than WASCA LASIK. [J Refract Surg 2001;17:S608-S612]
Iris-claw Phakic Intraocular Lens for High Myopia
Authors: Landesz Monika , van Rij Gabriel , Luyten Gregorius
Published: April 2021

ABSTRACT

PURPOSE: To evaluate the efficacy, safety, predictability, and stability of implanting a polymethylmethacrylate (PMMA) phakic intraocular lens (PIOL) (the Artisan myopia lens) to correct high myopia.

METHODS: An Artisan myopia lens was implanted in 78 consecutive eyes of 49 patients with preoperative myopia that ranged from -6.25 to -28.00 D. Mean patient age was 42.4 years. Mean follow-up was 10.7 months and all patients were followed for at least 6 months; 45 eyes had follow-up of 12 months, and 10 eyes had 24 months. The desired outcome was emmetropia in all eyes except for those eyes with preoperative myopia greater then -23.00 D.

RESULTS: Fifty-three eyes (67.9%) had a postoperative refraction at the last follow-up examination within ?1.00 D of emmetropia, and 39 eyes (50.0%) had a postoperative refraction ?within 0.50 D of emmetropia. The postoperative refraction remained stable during the entire follow-up period. Mean spectacle-corrected visual acuity improved from 20/32 preoperatively to 20/25 postoperatively. Mean postoperative uncorrected visual acuity was 20/32. There was no significant change in endothelial cell density from baseline. We did not encounter major complications.

CONCLUSION: Implantation of the Artisan myopia lens to correct high myopia resulted in a stable and fairly predictable refractive outcome. A significant endothelial cell change was not detected. [J Refract Surg 2001,1 7:634-640]
Effect of Acute Biomechanical Changes on Corneal Curvature After Photokeratectomy
Authors: Dupps William J , Roberts Cynthia
Published: April 2021

ABSTRACT

PURPOSE: Unintended hyperopia shift; is a common yet poorly understood complication of phototherapeutic keratectomy (PTK) that raises fondamental questions about the etiology of corneal curvature change in PRK and LASIK. We investigated the relative contributions of ablation profile and peripheral stromal thickening to intraoperative PTK-indueed central flattening, and propose a biomechanical model of the acute corneal response to central ablation.

METHODS: Fourteen de-epithelialized eye bank globes from seven donors underwent either broadbeam ablation (~100-??? depth, no programmed dioptric change) or sham photoablation in pairedcontrol fashion. Peripheral stromal thickness changes and the pattern of thickness loss across each ablation zone were evaluated by optical section image analysis as predictors of acute corneal flattening.

RESULTS: Relative to sham ablation, keratectomy caused significant anterior corneal flattening (-6.3 ? 3.2 D, P = .002). Concomitant peripheral stromal thickening (+57 ? 43 ??\, P = .01) was a significant predictor of acute hyperopic shift (r = 0.68, P - .047). Ablation pattern bias did not consistently favor hyperopia and was a poor lone predictor of hyperopic shift.

CONCLUSIONS: Unintended keratectomyinduced hyperopic shift is replicable in a human donor model and is associated with significant thickening of the unablated peripheral stroma. This biomechanical response may have a considerable impact on early refractive outcomes in PTK, PRK, and LASIK [J Refract Surg 2001;17:658-669]
Microwave Thermal Keratoplasty for Myopia: Keratoscopic Evaluation in Porcine Eyes
Authors: Trembly B Stuart , Hashizume Natsuko , Moodie Karen L , Cohen Kenneth L , Tripoli Nancy K , Hoopes P Jack
Published: April 2021

ABSTRACT

PURPOSE: Microwave thermal keratoplasty applies microwave energy to elevate the temperature of the paracentral stroma of the cornea to its thermal shrinkage temperature of about 600C. A suitable pattern of shrinkage in the paracentral cornea can flatten the central cornea. A surface cooling system preserves the epithelium during the procedure.

METHODS: Fourteen enucleated porcine eyes were treated with a prototype microwave thermal keratoplasty applicator that heated in a ring pattern with inner diameter of 3.2 mm and width of 0.7 mm. The change in corneal power was quantified by a videokeratoscope. Slit-lamp microscope examinations and histological assessments were made.

RESULTS: The 3-mm simulated keratometry reading showed an average of 6.60 ? 6.00 D (standard deviation) of flattening. The region of opacity associated with shrinkage extended to 62% (?26%) of the corneal thickness. The epithelium was intact in all eyes.

CONCLUSIONS: Microwave thermal keratoplasty applied in the paracentral cornea may flatten the central cornea. [J Refract Surg 2001;17:682-688]
Image Quality in Myopic Eyes Corrected With Laser in situ Keratomileusis and Phakic Intraocular Lens
Authors: Sarver Edwin J , Sanders Donald R , Vukich John A
Published: April 2021

ABSTRACT

PURPOSE: To compare image quality due to higher-order aberrations following laser in situ keratomileusis (LASIK) or implantation of phakic intraocular lens (PIOL) to correct high myopia.

METHODS: Postoperative wavefront examinations, normalized to a pupil size of 5.5 mm, were obtained for 19 LASLK and 20 PIOL eyes for the same surgeon over the same time period. Higherorder aberrations and simulated retinal images were compared.

RESULTS: For this small sample, the LASLK eyes yielded an average three times more spherical aberration and two times more coma than PIOL eyes. The effects of these differences were visualized using the simulated retinal images.

CONCLUSION: Spherical aberration and coma are the major differences between postoperative LASIK and PIOL higher-order aberrations, and simulated retinal images can be used to visualize these effects. [J Refract Surg 2003,19:397-404]
Technical Improvements in Photorefractive Keratectomy for Correction of High Myopia
Authors: Cennamo Giovanni , Rosa Nicola , Breve Maria Angelica , di Grazia Maria
Published: April 2021

ABSTRACT

PURPOSE: To evaluate the effects of hardware and software improvements in photorefractive keratectomy (PRK) for the treatment of highly myopic eyes.

METHODS: A retrospective study was carried out in 554 patients (582 eyes) with myopia between -7.00 and -17.00 D (mean -11.20 ± 3.60 D) who had undergone PRK using the Aesculap Méditée laser. Group 1 with a 5-mm-diameter single ablation zone; Group 2 with a 5-mm-diameter single zone surrounded by a 2-mm tapered transitional zone; Group 3 and Group 4, same as Group 2 but with the laser upgraded with a smoke aspiration control system (Group 3), and with a computer-controlled fluenee (Group 4).

RESULTS: In Group 1 at 2 years after PRK (50 eyes), 10 eyes (20%) were within ±1.00 D of attempted correction and 13 eyes (26%) were within ±2.00 D. In Group 2 at 2 years (118 eyes), 42 eyes (36%) were within ±1.00 D of attempted correction and 65 eyes (55%) were within ±2.00 D. In Group 3 at 2 years (43 eyes), 18 eyes (42%) were within ±1.00 D of attempted correction and 28 eyes (65%) were within ±2.00 D. In Group 4 at 2 years (47 eyes), 25 eyes (53%) were within ±1.00 D of attempted correction and 29 eyes (62%) were within ±2.00 D.

CONCLUSIONS: Software and hardware improvements facilitated PRK correction of high myopia with reasonable predictability, especially if a tapered transition zone was used. At 12 and 24-month follow-up, only the use of a tapered transition zone was associated with a statistically significant improvement in predictability. [J Refract Surg 2003;19:438-442]
Influence of Ablation Parameters on Refractive Changes After Phototherapeutic Keratectomy
Authors: Ginis Harilaos S , Katsanevaki Vikentia J , Pallikaris Ioannis G
Published: April 2021

ABSTRACT

PURPOSE: The aim of the current study was to control the hypothetical effects of decreased laser energy delivered to the peripheral cornea during phototherapeutic keratectomy (PTK) and provide quantitative calculation of induced low and high order aberrations.

METHODS: We employed a model eye to simulate the refractive effect of homogeneous laser corneal irradiation, as in PTK, for different laser fluences (range 125 to 225 mJ/cm2) and treatment depths up to 200 pm.

RESULTS: The hyperopic shift induced by the relatively lower energy delivered at the peripheral ablation zone during PTK was proportional to the treatment depth and inversely proportional to the energy fluence. The hyperopic shift calculated using the above ablation parameters was lower compared to previously reported clinical results. Higher order wavefront aberration (total root mean square) changes were of minimal significance for treatment depths up to 200 urn.

CONCLUSIONS: After PTK, a hyperopic shift cannot be attributed to the energy delivery method alone. Modification of laser energy delivery algorithms may only minimize PTK-induced hyperopia. [J Refract Surg 2003;19:443-448]
Conductive Keratoplasty for Low to Moderate Hyperopia: 1-year Results
Authors: Pallikaris Ioannis G , Naoumidi Tatiana L , Panagopoulou Sophia I , Alegakis Athanasios K , Astyrakakis Nikolaos I
Published: April 2021

ABSTRACT

PURPOSE: To assess the safety, efficacy, and stability of conductive keratoplasty in the treatment of low to moderate hyperopia and evaluate the impact of the procedure on the quality of vision.

METHODS: Thirty-six eyes (25 patients; 13 female and 12 male) were treated for hyperopia up to +3.25 D with a Refractec ViewPoint CK system and followed for 1 year. Mean age was 50.2 ± 8.7 years (range 31 to 71).

RESULTS: Before surgery, mean spherical equivalent refraction was +1.90 ± 0.60 D (range +1.00 to +3.25 D), decreasing at 1 year after conductive keratoplasty to -0.06 ± 0.80 D, and was within ±0.50 D of emmetropia in 68% (24 eyes) and within ±2.00 D in all eyes. Twelve months after conductive keratoplasty, uncorrected visual acuity was 20/20 or better in 19 eyes (50%) and 20/40 or better in 32 eyes (89%). No eye lost ≥2 Snellen lines or had induced cylinder ≥2.00 D. The mean root mean square values for higher order optical aberrations were 0.060 ± 0.039 before and 0.174 ± 0.170 at 3 months after surgery. No statistically significant changes in contrast sensitivity were noted.

CONCLUSIONS: Conductive keratoplasty for low to moderate hyperopia provided safe, effective, and stable results both in refraction and quality of vision. [J Refract Surg 2003;19:496-506]
Diameters of Topographic Optical Zone and Programmed Ablation Zone for Laser in situ Keratomileusis for Myopia
Authors: Partal Andreea E , Manche Edward E
Published: April 2021

ABSTRACT

PURPOSE: To compare topographic optical zones with programmed ablation zone settings of eyes treated with laser in situ keratomileusis (LASIK) for myopia using the VISX S2 excimer laser.

METHODS: Two-hundred three eyes treated with LASIK using the VISX S2 excimer laser were retrospectively evaluated to determine the size of the topographic optical zone. Three to six months after LASIK, the topographic optical zone was measured at the zone of highest curvature on topography and subtraction topography. Eyes were divided into four groups (A, B, C, D) in order of increasing myopia.

RESULTS: When the topographic optical zone was compared with the programmed ablation zone, an optical zone reduction of 0.5 ± 0.1 mm and 0.4 ± 0.1 mm was found for the longest and shortest diameters, respectively. For eyes with spherical ablation zones, this reduction was 0.6 * 0.1 mm and 0.4 ± 0.1 mm shorter than the programmed horizontal and vertical dimensions. Groups A, B, C, and D, in order of increasing myopia, all showed reductions of approximately 0.5 ±0.1 mm for the longest and 0.3 to 0.4 ± 0.1 mm for the shortest diameters of the optical zone.

CONCLUSIONS: The topographic optical zone was reduced from the programmed ablation zone. This reduction was statistically significant for both elliptical and spherical ablations, and seemed to be independent of the amount of myopia. [J Refract Surg 2003;19:528-5331
Aberration Analyses Needed for FDA Evaluation of Safety and Effectiveness of Wavefront-guided Refractive Surgical Devices
Authors: Drum Bruce A
Published: April 2021

ABSTRACT

PURPOSE: Manufacturers of refractive surgical lasers are seeking Food and Drug Administration (FDA) approval for refractive surgery based on wavefront measurements rather than manifest refractions. This article draws attention to the need for better understanding of the relationship between aberrations and visual function and better testing methods for evaluating safety and effectiveness of wavefront-guided refractive surgery.

METHODS: Before U.S. market approval for a new medical device, the FDA must determine whether the manufacturer has provided reasonable assurance that the device is safe and effective for its intended use, based on valid scientific evidence. The issues discussed here are based on FDA reviewers' experiences in evaluating Investigational Device Exemption (DDE) and Premarket Approval (PMA) applications for wavefront-guided refractive lasers.

RESULTS: Even an optimal wavefront correction can provide only a marginally greater visual function benefit than a conventional spherocylindrical correction in a normal eye. Actual benefits are even smaller or nonexistent because variability from uncontrollable sources (eg, healing, aging, accommodation, pupil size, or ocular biomechanical effects) are typically larger than the errors treated. The effects of higher order aberrations and aberration changes on visual function are complex and poorly understood.

CONCLUSIONS: The FDAs need for better tools to assess safety and effectiveness of wavefrontguided refractive surgery has stimulated major research efforts within the vision, ophthalmic, and Optometrie research communities. More research is needed to better understand the relationship between aberrations and visual function, and to be able to predict the visual effects of specific aberration changes in individual eyes. This research would have been more appropriately done before rather than after clinical trials for wavefrontguided refractive lasers. [J Refract Surg 2003;19: S588-S591]
From Scattering to Wavefronts-What's in Between?
Authors: Mrochen Michael , Semchishen Vladimir
Published: April 2021

ABSTRACT

PURPOSE: Some optical errors are too localized and random to be detected by commercial wavefront devices and Zernike polynomial expression. We looked beyond aberrations defined by Zernike expression to discuss implications of fine irregularities associated with highly aberrated corneal surfaces and complex surface roughness that can lead to light scattering.

METHODS: Most fine irregularities are related to postoperative surface roughness, complexities of corneal ablation, and the laser in situ keratomileusis (LASIK) flap. These can be characterized mathematically by a random function that includes local surface tilts, the correlation radius of irregularities (Ic), surface roughness, and other terms. The Kirchoff method of scatter analysis characterizes fine surface irregularities by replacing each point on the surface with a tangential plane, allowing it to be governed by Snellen and Fresnel laws,

RESULTS: The joint action of the continuum of microbeams defines a complex point spread function that can be expressed by the Strehl ratio. Small, highly irregular steep central islands and flap striae may not be adequately detected by Zernike expression and may have a surface irregularity diameter of 0.1 to 2.0 mm and height of 10 to 20 pm that results in a reduced Strehl ratio below 0.8. Laser ablation inhomogeneities may have dimensions of 1 to 10 urn, resulting in a root mean square tilt value approaching 1.0 and a Strehl ratio below 0.5.

CONCLUSION: Corneal surface irregularities after laser vision correction may induce significant optical aberrations and distortions apart from classical wavefront or scattering errors. As these may not be detected by commercial wavefront devices, and yet contribute to the degradation of optical performance, alternate techniques should be evaluated to detect and describe these surface irregularities. [J Refract Surg 2003;19:S597-S601]
Intraoperative Wavefront Monitoring During Laser Thermal Keratoplasty
Authors: Krueger Ronald R , Gomez Pedro , Herekar Satish
Published: April 2021

ABSTRACT

PURPOSE: Low energy laser thermal keratoplasty (LTK) is being proposed as an alternative to conventional holmium LTK in an effort to minimize corneal tissue necrosis, regression, and induced astigmatism. Real-time wavefront monitoring during surgery is also being proposed as a method for regulating induced aberrations and the treatment end point. We evaluated the feasibility of intraoperative wavefront monitoring during low energy LTK.

METHODS: An investigational prototype system combining a Sunrise Hyperion laser with a Shack-Hartmann wavefront sensor (Wavefront Sciences COAS) was used to treat 20 hyperopic eyes with a low energy application of eight spots of 18mJ/shot (144mJ/pulse) at 5 Hz in two rings of 6 mm and 7-mm diameter, while monitoring the treatment with real-time dynamic wavefront sensing up to 10 captures/second of 4th order Zernike data.

RESULTS: The integrated wavefront-monitored LTK unit showed good stability in measuring dynamic intraoperative wavefront refractions before, during, and after the low energy LTK treatment. The readings did not interfere with the application of holmium laser pulses, nor did the LTK treatment distort the captured wavefront readings. A steady improvement of the wavefront-derived spherical equivalent refraction followed the laser treatment pattern, with a mean attempted spherical equivalent refractive change of 1.66 D and mean achieved change of 1.71 D.

CONCLUSION: Intraoperative wavefront monitoring was feasible during low energy LTK. With future adaptation, it might be possible to dynamically relay the captured wavefront information to the laser during ongoing treatment, to intraoperatively control the surgical endpoint for multiple aberration terms. [J Refract Surg 2003;19: S602-S607]
Ferrara Intrastromal Corneal Ring Segments for Severe Keratoconus
Authors: Miranda Danielle , Sartori Marta , Francesconi Claudia , Allemann Norma , Ferrara Paulo , Campos Mauro
Published: April 2021

ABSTRACT

PURPOSE: lntrastromal Ferrara ring segments were inserted in eyes with severe keratoconus to evaluate safety and efficacy of this procedure.

METHODS: lntrastromal Ferrara ring segments were placed in 36 eyes of 35 patients with severe keratoconus, who were evaluated after 12 months of follow-up. All patients had highly disabling visual acuity, contact lens intolerance, and a previous indication for penetrating keratoplasty. Statistical analysis included preoperative and postoperative uncorrected visual acuity, best spectacle-corrected visual acuity, manifest refraction, anterior chamber depth, keratometry, and pachymetry.

RESULTS: No patient had a loss of visual acuity. Uncorrected visual acuity improved in 28 eyes (77.78Cf) and best spectacle-corrected visual acuity improved in 29 eyes (80.56%). Spherical equivalent refraction decreased from -7.29 ± 3.12 D to -4.80 ± 3.04 D at 12 months after Ferrara intrastromal ring segment implantation. Corneal topography and ultrasound biomicroscopy showed corneal flattening, demonstrated by thinning of the central cornea and a reduction in anterior chamber depth. Segment decentration occurred in one eye (2.7%), asymmetric positioning of the segments in two eyes (5%), inadequate depth in two eyes (5%), migration of the segments in two eyes (5%), segment extrusion in five eyes (13.8%), conjunctivitis in one eye (2.7%), bacterial keratitis in one eye (2.7%), and hydrops in one eye (2.7%).

CONCLUSIONS: With these early results, Ferrara intrastromal ring segments appear to be an alternative for the treatment of severe keratoconus. [J Refract Surg 2003;19:645-653]
Use of a Short Wavelength Filter in an Operating Microscope
Authors: Keates Richard H , Armstrong Paul F
Published: April 2021

ABSTRACT

There is growing concern over the potential phototoxic effect on the patient's retina from the coaxial illumination of the operating microscope. By replacing the existing red-free filter in the body of a Zeiss operating microscope, with a 470-nm filter, the ultraviolet and low wavelength blue light can be easily and effectively filtered from the transmitted white light. In this location, the filter can be quickly and safely rotated into or out of line with the transmitted light depending on the preference of the ophthalmologist.
Sickle Cell Hyphema With Secondary Glaucoma in a Non-Black Patient
Authors: Greenwald Mark J , Crowley Timothy M
Published: April 2021

ABSTRACT

A 5-year-old Mexican-American boy developed marked elevation of intraocular pressure in association with a small traumatic hyphema. Laboratory studies prompted by this clinical presentation revealed that the child had sickle trait. Pressure returned to normal after surgical evacuation of blood from the anterior chamber. Sickle cell hemoglobinopathy should be considered in the differential diagnosis of secondary glaucoma following blunt ocular trauma even in non-black patients.
Ectopic Lacrimal Gland Tissue of the Orbit and Sclerosing Dacryoadenitis
Authors: Margo Curtis E , Naugle Thomas C , Karcioglu Zeynel A
Published: April 2021

ABSTRACT

A 28-year-old man with unilateral proptosis was found to have sclerosing dacryoadenitis and ectopic lacrimal gland tissue of the orbit. The unusual combination simulated invasive adenocarcinoma of the lacrimal gland both clinically and histopathologically. Based on clinical and experimental observations, we propose that the acinar gland atrophy and fibrous replacement of the lacrimal gland and of the heterotopic tissue was the result of a primary developmental abnormality associated with obstruction to normal gland outflow. Physician awareness that ectopic lacrimal gland tissue in the orbit can be affected by sclerosing dacryoadenitis is probably the most critical factor in establishing the correct diagnosis.
Acellular Proteinaceous Film on Lens Implants: A Typical Reactive Situation in Complicated Cases
Authors: Wolter J Reimer
Published: April 2021

ABSTRACT

The more or less complete absence of fibroblast-like cells from reactive membranes on the optics of lens implants is demonstrated in four clinically complicated cases of pseudophakia. This is associated with preservation of the film-like proteinaceous part of these membranes. In these cases the lack of cells is believed to be secondary in nature and a sign of significant adaptation difficulties.
Lacrimal Gland Duct Cysts
Authors: Hornblass Albert , Herschorn Brian J
Published: April 2021

ABSTRACT

Lacrimal gland duct cysts develop insidiously in the superotemporal cul de sac. They may be preceded by trauma, infection, or inflammation of the conjunctiva. They are often asymptomatic but may induce discomfort, a sensation of fullness, a visible mass, lid distortion or ectropion. Fluctuation in size with weeping or environmental stimuli is seen. Histopathology is variable. Six cases are described to demonstrate the features. Complete excision of each cyst by meticulous dissection through a conjunctival approach was performed. Total resection is the optimal technique to prevent recurrence.
Gentle, Technically Simple Repositioning of Displaced Lacrimal Tubing
Authors: Gonnering Russell S
Published: April 2021

ABSTRACT

Lateral displacement at the medial canthus is the most common complication following lacrimal intubation. Current procedures for dealing with this situation involve the removal of the tubing, and are either technically difficult or else involve retrograde passage of the knotted silicone through one of the canaliculi. By passing both probes of a second intubation set through the same punctum, the loop of the displaced tubing can be captured and gently repositioned without removal. This is particularly useful with early displacement of the tubing following microsurgical repair of a canalicular laceration.
A New Lens for Argon Laser Trabeculoplasty
Authors: Ritch Robert
Published: April 2021

ABSTRACT

Most ophthalmologists perform laser trabeculoplasty with a Goldmann three-mirror lens with an anti-reflective coating. The view of the superior angle, which is frequently narrower than the inferior angle, often presents difficulties in treatment. A lens has been devised which gives improved views of the superior portion of the angle. Plano-convex buttons provide magnification and increase resolution for difficult situations.
Wills Eye Hospital Traumatic Hyphema Study
Authors: Cassel Gary H , Jeffers John B , Jaeger Edward A
Published: April 2021

ABSTRACT

Hyphema associated with nonpenetrating ocular trauma is a common cause for emergency hospitalization. The complications which result from this form of eye injury can cause permanent impairment of vision.

Complications within the study population were reviewed. Analysis found a 16% rate of rebleeding, with the majority of these occurring within three to four days following the traumatic event. Unfortunately, no risk factors could be identified to help predict which patients were more at risk of complications. However, management of the complications which did develop in the study population was effective.
A Canthal Siphon Wick
Authors: Mills Richard P
Published: April 2021

ABSTRACT

A simple wick can be fashioned from a cellulose surgical sponge and used to drain fluid from the ophthalmic surgical field.
Anterior Chamber Washout for Traumatic Hyphema
Authors: Belcher C Davis , Brown Steven V L , Simmons Richard J
Published: April 2021

ABSTRACT

A surgical approach that involves paracentesis and gentle anterior chamber washout and minimal surgical trauma is presented for dealing with traumatic hyphema. This technique taught by Dr. Paul Chandler produces excellent results and is safe, simple, and without need for elaborate instrumentation.
Combined Trabeculectomy and Cataract Extraction
Authors: Dellaporta Angelos
Published: April 2021

ABSTRACT

Combined trepanotrabeculectomy (TTE) and intracapsular cataract extraction for advanced cataract and severe open angle glaucoma proved to be successful in 84% of the operated eyes which were followed for one to 11 years. Complications were infrequent as compared to other combined procedures. The frequency of postoperative flat anterior chamber in particular was much lower. In 77% of the eyes the surgical scars were covered by normal conjunctiva without evidence of extraocular filtration. No avascular cystic blebs formed. The same operation performed as a secondary procedure seems to be equally successful. Eight eyes, which previously had successful trepanotrabeculectomy, developed cataract, which was removed without impinging on the function of the trabeculectomy scars. If the two operations are to be performed in separate sittings, it is advisable to perform the TTE first, followed by cataract extraction.
Vision Parameters in Krypton and Laser Photocoagulation of Subfoveal Neovascular Membranes
Authors: Melrose Mark A , Magargal Larry E , Donoso Larry A , Goldberg Richard E , Edmonds Susan E
Published: April 2021

ABSTRACT

A prospective study of 78 patients, treated with krypton red laser (KRL) photocoagulation, who had senile macular degeneration (SMD) and subretinal neovascular membranes (SRNVM) located within 200u of the center of the foveal avascular zone (FAZ), was undertaken to determine if complete eradication of the SRNVM would minimize the resultant foveal scar size and retain the maximal useful functional vision as compared to untreated fellow eyes with a disciform scar.

The typical patient profile with SMD and subfoveal SRNVM included: average age, 73.6 years; caucasian, 99%; females, 62%; lightly pigmented iris, 70%; hyperopic refractive error, 93%; and evidence of bilateral involvement with either predisciform or disciform lesions, 73%.

In comparing eyes treated with KRL having 100% FAZ involvement with fellow untreated eyes having disciform scars, the latter had poorer average visual acuity (44% vs 100% ≤20/200), scars which were an average of five times larger (8.4 vs 38.6 sq mm) and scotomas which were an average of six times larger (15.7 vs 90 sq cm) as determined by new microcomputer technology.

In all bilaterally affected cases, eyes with smaller scars and scotomas required less magnification from a low vision aid to read continuous standardized 1M print. Sixteen of 17 patients (94%) preferred the low vision aid for their treated eye. These preliminary results suggest that treatment of SRNVM within the FAZ using KRL may be successful in arresting the progressive macular hemorrhagic-exudative damage typical of untreated cases which culminate in loss of central visual function. Successful treatment, by preserving areas of paracentral fixation, can enhance the chances of visual rehabilitation using conventional low vision aids.
Lid Retraction and Levator Aponeurosis Defects in Graves' Eye Disease
Authors: Frueh Bartley R , Musch David C , Garber Frank W
Published: April 2021

ABSTRACT

Vertical palpebral fissure determinants and lid crease height were measured in patients with Graves' eye disease (GED) and in normal subjects. The fissure and crease height are positively correlated with exophthalmometer readings in each group. Compensatory levator aponeurosis defects are shown to occur in patients with GED. These, along with the effect of exophthalmos on the lower lid position, the observation that the lower lid is closer to the inferior limbus than the upper lid is to the superior limbus in normal subjects, and the effect of contracture of the inferior rectus on the lower lid position, explain why inferior scleral show is found to be greater than superior scleral show in patients with GED. Thus, lid retractor surgery in GED patients should be performed only after the palpebral fissure, levator function, and lid crease height stabilize, and after any contemplated surgery that would alter the exophthalmos and extraocular muscles has been performed.
Retrobulbar Anesthesia and Orbicularis Akinesia
Authors: Martin Stephen R , Baker Sterling S , Muenzler W Stanley
Published: April 2021

ABSTRACT

After noting that simple retrobulbar injection often caused orbicularis akinesia, we evaluated this phenomenon prospectively. A total of 50 patients were given a standard injection using 3 cc of a 50-50 mixture of 0.75% bupivacaine and 2% lidocaine with epinephrine and hyaluronidase. The entire 3 cc was injected into the muscle cone through an inferolateral lid entry using a 35-mm retrobulbar needle of either 23- or 27-gauge. Injection was considered successful if orbicularis function was sufficiently reduced to proceed with an intraocular case after a single retrobulbar injection. If facial nerve block was necessary or if the patients lid moved during surgery, then the procedure was considered a failure. Of the 50 patients, 44 achieved adequate akinesia of the orbicularis after retrobulbar injection alone, giving a success rate of 88%. Benefits of this method include lower drug volume, decreased chance for direct nerve damage during a facial nerve block, less pain, less ecchymosis, and less edema following surgery.
Temporal Branch Retinal Vein Obstruction: A Review
Authors: Magargal Larry E , Kimmel Andrew S , Sanborn George E , Annesley William H
Published: April 2021

ABSTRACT

Two hundred forty-six eyes with temporal branch retinal vein obstruction (TBRVO) were studied prospectively. Of the 85 eyes not receiving laser treatment, 35 (41%) presented with ≥20/50 vision and 89% remained in this group; whereas, 29 eyes (34%) presented with ≤20/200 vision and only 17% improved. Of the 161 eyes receiving laser, 40 (25%) had ≥20/50 vision pre-treatment and 75% remained in this group; whereas, 64 eyes (40%) had ≤20/200 vision pre-treatment and 50% improved. The average final VA (20/70 vs 20/100), risk of developing neovascularization in ischemic TBRVO (3% vs 34%) and risk of vitreous hemorrhage in proliferative TBRVO (10% vs 57%) were all significantly better in treated eyes (p ≤ 0.01).
Aiming Accuracy in Ophthalmic Laser Microsurgery
Authors: Rol Pascal , Fankhauser Franz , Kwasniewska Sylwia
Published: April 2021

ABSTRACT

A number of aiming/focusing systems, oriented toward guiding the treatment beams of photodisruptive, high power Nd:YAG lasers, are analyzed and evaluated. A system, consisting of two frequency modulated, rotating laser beams, which outline the Nd:YAG laser beam shape, is shown to be the optimal solution.
The Effects of Nonfixated Lower Lens Haptics of Binkhorst Lenses on Corneal Endothelial Cell Density
Authors: Richards Brad W , Richards Winn L , Olson Randall J , Richards Scott C
Published: April 2021

ABSTRACT

At specified intervals up to 56 months postoperatively, we took central corneal endothelial cell measurements of 52 patients who had undergone extracapsular cataract extraction (ECCE) with placement of a Heyer-Schulte IC-10 iridocapsular intraocular lens. We then compared the endothelial cell density of patients in whom the lower lens haptic was fixated within the capsule with those in whom it was nonfixated. We found that nonfixation of the lower lens haptic, which in essence converts the irido-capsular lens to an iris-supported lens, does not cause continuing endothelial cell loss.
Sodium Hyaluronate (Healon®) in Closed Vitrectomy
Authors: Folk James C , Packer Andrew J , Weingeist Thomas A , Howcroft Michael J
Published: April 2021

ABSTRACT

Healon® was implanted into the vitreous cavity of 33 eyes at the conclusion of pars plana vitrectomy. In aphakic eyes, Healon diffused rapidly into the anterior chamber, reducing the length of effective tamponade posteriorly and causing marked elevations of intraocular pressure. In phakic diabetic eyes, Healon appeared to trap hemorrhage mechanically from bleeding fibrovascular stumps posteriorly. It may therefore reduce the risk of opacifying vitreous hemorrhage after vitrectomy in phakic eyes with active neovascularization.
Blindness From Retrobulbar Injection into the Optic Nerve
Authors: Pautler Scott E , Grizzard W Sanderson , Thompson Lawrence N , Wing Glenn L
Published: April 2021

ABSTRACT

We report two patients with marked visual loss due to injection within the optic nerve sheath. Findings included severe visual loss, optic disc edema, retinal edema, and intraretinal, preretinal, and vitreous hemorrhage. A review of similar cases in the literature reveals a common but ill-advised use of sharp retrobulbar needles with the technique of retrobulbar injection described by Atkinson. A modified technique which limits the risk of optic nerve trauma is described.
Müller's Muscle in the Treatment of Upper Eyelid Ptosis: A Ten-Year Study
Authors: Putterman Allen M , Fett David R
Published: April 2021

ABSTRACT

Müllers muscle is a sympathetically innervated muscle that can be resected to treat upper eyelid ptosis.

Candidates for the ptosis procedure are those whose upper lids elevate to a normal level following instillation of phenylephrine hydrochloride drops into their upper ocular fornix. A specially designed clamp is applied to 6.5 to 9.5 mm of conjunctiva and Müller's muscle above the superior tarsal border. A suture is run distal to the clamp, connecting conjunctiva and Müller's muscle to the superior tarsal border; then, the tissues held in the clamp are resected. In a ten-year study of this procedure, 90% of the lids with acquired ptosis and 100% of those with congenital ptosis were within 1.5 mm of the level of the opposite lid postoperatively. Only two of 232 treated lids required additional surgery.