bluuebunny/crossref_metadata_2025_split huggingface dataset:
Circular Keratotomy for the Correction of Astigmatism
Authors: Krumeich Jorg H , Knuelle Alfred 
Published: April 2021

ABSTRACT
BACKGROUND: Mathematical and physical considerations that are contained in Gauss' law lead to the concept of a circular cut for the correction of corneal astigmatism.
METHODS: The method applied is the coupling of the aspheric corneal surface to the spherical obturator of the Guided Trephine System® and cutting of 90% of the parenchyma. Nineteen human eyes were treated with this technique, using a double-running suture closure.
RESULTS: Results of reduction of astigmatism can regularly be obtained but are of different amounts depending on the origin of asiigmaiism. Mean preoperative refractive astigmatism was 5.41 diopters and mean postoperative refractive astigmatism was 1.34 D. Six eyes required additional tranverse arcuate keratotomy.
CONCLUSIONS: The procedure is effective, but the results are variable. It may be improved by the use of obturators that fit the radius of curvature of the cornea. [Refract Corneal Surg 1992;8:204-210.)
Photokeratitis From Subablative 193-Nanometer Excimer Laser Radiation
Authors: Krueger Ronald R , Sliney David H , Trokel Stephen L 
Published: April 2021

ABSTRACT
BACKGROUND: Photokeratitis is a side effect of UV light exposure whereby the corneal epithelium is photochemically injured in a time delayed fashion. UV light exposure in the far ultraviolet wavelength range has not previously been observed. This study addresses the concern of photokeratitis from subablative 193-nanometer excimer laser light.
METHODS: Dutch belted rabbit corneas were irradiated with subablative 193-nanometer excimer laser light over a wide range of total energy exposures, and examined by slit lamp biomicrosope for signs of photokeratitis. Photokeratitis was identified by epithelial haze and stippling.and rose bengal and flourescein staining at varied time intervals between ½ to 26 hours post exposure.

RESULTS: At threshold energy exposures of 1.0 to 1.5 J/cm
p 2
, an immediate superficial epithelial haze was seen which disappeared within several hours. At higher energy exposures of 10 J/cm
p 2
, a delayed photokeratitis with deep rose bengal and even fluorescein staining was seen. This latter delayed photokeratitis resembles that of longer UV wavelengths and is due to excimer laser fluorescence, whereas the former is a direct response of the 193-nanometer light. The percentage of excimer laser light undergoing fluorescence is calculated as less than 1%.

CONCLUSIONS: The potential side effects and hazards of scattered 193-nanometer radiation during excimer laser surgery are extremely limited because of the shorter penetration depth of direct excimer radiation and the minimal fluorescent emission of longer UV wavelengths for energy exposures within the realm of clinical use. [Refract Corneal Surg 1992;8:274-279.)
Differences Between Objective and Subjective Refractions After Radial Keratotomy
Authors: Russell Gregg E , Bergmanson Jan P G , Barbeito Raphael , Cross Warren D 
Published: April 2021

ABSTRACT
BACKGROUND: In patients who are free of pathology, automatic refractions have shown close agreement with the subjective refractions. Clinical experience indicated that the normally strong relationship between objective and subjective refraction is significantly weakened as a result of radial keratotomy.
METHODS: Seventy-two patients were refracted before and after surgery, objectively with a Humphrey Model #510 autorefractor and subjectively using a binocular refraction procedure without cycloplegia. All patients were free of ocular disease and had preoperative myopia ranging from -1.00 to -9.00 diopters as determined by the subjective spherical equivalent.
RESULTS: The results indicated that the preoperative difference between the mean spherical automatic and subjective refractions was a clinically acceptable 0.25 diopter. However, postoperatively, there was a statistically significant difference of 1.25 D with the automatic refractor determining more myopic refractions. Subsequent analysis revealed that the age of the patient had a direct bearing on this finding with patients less than 40 years of age showing more minus in the automatic refraction than patients 40 years and older.
CONCLUSIONS: The postoperative discrepancy between the two refractions may be explained by induced optical aberrations and may contribute towards the visual fluctuations experienced by radial keratotomy patients. It is postulated that the inconsistency in refractive determination is due to optical distortion since the age dependence of this effect may be related to the reduction of pupil size that occurs with aging. In the radial keratotomy patient, the practitioner is faced with a more complex and uncertain refraction that may vary according to refractive procedures used and other factors such as pupil size. Refract Corneal Surg 1992;8:290-295.)
Four-Incision Radial Keratotomy for High Myopia After Penetrating Keratoplasty
Authors: Gothard Todd W , Agapitos Peter J , Bowers Richard A , Mma Stephen , Chen Varda , Lindstrom Richard L 
Published: April 2021

ABSTRACT
BACKGROUND: High amounts of myopia can frequently produce anisometropia and limit visual rehabilitation by conventional means in eyes with clear corneal grafts. This condition is frequently coupled with large amounts of astigmatism. Fourincision radial keratotomy provides a way to reduce myopia in normal individuals. In our present study, we used the technique of four- Incision radial keratotomy to reduce myopia in a group of keratoplasty patients who failed conventional visual rehabilitation. Arcuate or transverse keratotomy was used in conjunction with radial keratotomy in eyes with high amounts of astigmatism.
METHODS: This study retrospectively examined a group of 1 1 eyes with penetrating keratoplasty which underwent four-incision radial keratotomy for the treatment of visually disabling myopia. The radial incisions were placed in the graft, inside the graft- host interface. Seven eyes underwent concomitant arcuate relaxing incisions at the grafthost interface for treatment of associated astigmatism. One additional eye had paired straight transverse incisions for the treatment of astigmatism. The mean postoperative follow up was 16 months (range, 3 months to 5 years).
RESULTS: There was a mean reduction of the spherical equivalent refraction of 3.48 diopters (D) (range, 0.25 to 7.75 D). The eight eyes undergoing astigmatic surgery showed a mean reduction in keratometric astigmatism of 2.25 D (range, -6.75 to +6.50 D) and refractive astigmatism of 4.63 D (range, - 1.50 to -9.50 D). Nine of the 1 1 eyes had stable or improved best spectacle corrected visual acuity. Two eyes had reduction of best spectacle corrected visual acuity- one due to development of irregular astigmatism and one due to worsening of preexisting macular edema.
CONCLUSIONS: Four-incision radial keratotomy can reduce myopia after penetrating keratoplasty when the patient is unable to tolerate spectacle or contact lens correction. It can be combined with relaxing Incisions or transverse keratotomy to reduce astigmatism. There is a high amount of variability, and predictability is currently limited by the complex topographical changes occurring in corneal transplants. Complex corneal biomechanical changes may predispose these eyes to the development of irregular astigmatism. Refract Corneal Surg 1993;9:51-57.)
RESUME
INTRODUCTION: La myopie forte donne fréquemment une anisométropie qui limite la guérison visuelle chez les patients post- keratoplasties, même si le greffon reste claire. Ces malades sont souvent fortes astigmates, aussi. Comme la kérafofomie radiare à quatre incisions réduit la myopie chez les yeux autrement normaux, nous en avons pratiqué chez les myopes fortes post-kératoplasties qui n'ont pas supportées la correction optique traditionelle. Les incisions arciformes ou transverses furent utilisées avec la kératotomie radiare chez les patients fortes astigmates.
Double Descemet's Membrane in Penetrating Keratoplasty
Authors: Archila Eduardo Arenas , Cabrera Marco F Ramirez , Alviar Alexandra Mieth 
Published: April 2021

ABSTRACT
A rare complication of penetrating keratoplasty is incomplete removal of the host Descemet's membrane, which can progressively become opaque. Utilizing a Nd:YAG laser, we opened the opaque membrane, improving visual acuity from 20/400 to 20/100.(Refracf Corneal Surg 1993;9;6566.)
Effects of Ablation Diameter, Depth, and Edge Contour on the Outcome of Photorefractive Keratectomy
Authors: O'Brart David P S , Corbett Melanie C , Verma Seema , Heacock Greg , Oliver Katherine M , Lohmann Chris P , Muir Malcolm G Kerr , Marshall John 
Published: April 2021

ABSTRACT
PURPOSE: To investigate the effects of the ablation diameter, depth, and edge contour on the outcome of excimer laser photorefractive keratectomy (PRK).
METHODS: A prospective study was conducted in which 60 patients (60 eyes) were randomly allocated to 5.00-mm, 6.00-mm, or 5.00 to 6.00-mm multizone treatment groups. All eyes underwent a -6.00 diopter (D) correction using a Summit Omnimed excimer laser.
RESULTS: In eyes treated with 6.00-mm diameter zones, the initial hyperopic shift was reduced, with significant differences at 1 and 4 weeks (p<0.01). At 6 and 12 months, the refractive changes were closer to the intended correction with 6.00-mm diameters. The predictability of PRK was improved with 6.00-mm zones, with a significant reduction in variance of the refractive changes, at all stages postoperatively (p<0.05 to p<0.001).
Objective measurements of haze were significantly less at 1, 3, and 6 months with 6.00-mm ablations (p<0.05). There were no differences between the 5.00-mm and the 5.00- to 6.00-mm multizone groups.
Computerized measurements of "night" halo were significantly smaller in the 6.00-mm treatment group at 1 week and 1 month (p<0.05). At 12 months, two patients treated with 5.00-mm zones and three with the 5.00- to 6.00-mm multizone complained of severe night vision disturbances. No 6.00-mm eyes were similarly affected.
CONCLUSIONS: Treatment with a 6.00-mm spherical ablation diameter produced less initial overcorrection, improved predictability, and was associated with a reduction in postoperative halos and night vision disturbances. Creating a superficial blend zone with a 5.00- to 6.00-mm multizone treatment had no beneficial effect on the outcome. [J Refract Surg. 1996;12:50-60.]
Attitudes of Successful Contact Lens Wearers Toward Refractive Surgery
Authors: Migneco Mary K , Pepose Jay S 
Published: April 2021

ABSTRACT
BACKGROUND: Traditionally, spectacle wearers and contact lens failures have been the patient population targeted for refractive surgery. We surveyed successful contact lens wearers to determine their attitudes toward refractive surgery.
METHODS: One hundred thirty-three consecutive successful myopic contact lens wearers older than 21 years were requested to read information regarding both radial keratotomy and excimer photorefractive keratectomy and complete a questionnaire. We report on the relationship between interest in undergoing radial keratotomy or photorefractive keratectomy and various patient parameters.
RESULTS: More than 75% of those surveyed indicated that they would consider either procedure at any time in the future. The only statistically significant correlation found was that patients younger than 40 more frequently expressed an interest in undergoing radial keratotomy than patients older than 40. Nearly 70% of those surveyed would not spend more than $500 per eye for either procedure, and most patients grossly underestimated the costs associated with contact lens wear.
CONCLUSIONS: In addition to spectacle wearers and contact lens failures, successful contact lens wearers can also be considered potential candidates for refractive surgery, provided it can be offered at a cost acceptable to them and if concerns regarding surgical side effects are addressed to satisfaction. This group does not appear to represent "early adapters" to new refractive technologies. The greatest interest was expressed by those younger than 40 years. [J Refract Surg. 1996;12:128-133.]
Penetrating Keratoplasty and Transsclerally Suture-Fixated Intraocular Lenses
Authors: Kandarakis Artemios S , Doulas Konstatinos G , Amariotakis Apostolos G 
Published: April 2021

ABSTRACT
BACKGROUND: One of the options the surgeon has, in the absence of lens capsule in an eye to be rendered pseudophakic, is a transsclerally sutured posterior chamber intraocular lens. This procedure can be combined with penetrating keratoplasty, in aphakic or pseudophakic covered edema.
METHODS: We studied retrospectively the results of the first 10 cases of bullous keratopathy in which we performed penetrating keratoplasty combined with transsclerally suture fixated intraocular lenses.
RESULTS: Nine grans remained transparent and 1 became opaque due to graft rejection with a mean follow up of 26.4 months. Postoperative visual acuity was improved in 7 eyes, remained the same in 2 and became worse in 1 (graft rejection) The poor postoperative visual acuity in 2 eyes was attributed to cystoid macular edema. All sutured intraocular lenses remained in situ; there was no apparent degradation of the Prolene suture. Two eyes developed postoperative medically controlled glaucoma.
CONCLUSIONS: Intraocular lens scleral fixation with sutures, combined with penetrating keratoplasty, seems to be a good procedure for visual rehabilitation for aphakic or pseudophakic bullous keratopathy. [J Refract Surg. 1996;12:S304-S306.]
Inflammatory Cells, Refractive Regression, and Haze After Excimer Laser PRK
Authors: Ramirez-Florez Susana , Maurice David M 
Published: April 2021

ABSTRACT
OBJECTIVE: To examine the role of inflammatory cell invasion and aspects of tissue reaction on refractive regression and corneal haze after myopic PRK in rabbits.
METHODS: Measurements were made for 12 weeks postoperatively of haze intensity, corneal topography, tear cytology, inflammatory cell invasion, subepithelial fibroblast density, and the thickness of the newly laid down connective tissue and of the regrown epithelium.
RESULTS: Inflammatory cell invasion could be prevented by fitting a soft contact lens, but this had no effect on the haze or the regression. Haze intensity correlated with subepithelial fibroblast proliferation but not with new connective tissue formation or epithelial hyperplasia. Neither connective tissue nor epithelium regrew in the form of a lens and thus they could not account for regression. Intensive treatment with corticosteroids resulted in a marked reduction in postoperative haze and a slight lessening of long-term regression. Correspondingly, it reduced fibroblast proliferation.
CONCLUSIONS: Haze appears, at least in part, to be a result of fibroblast proliferation. Regression is possibly caused by slow distortion of existing tissue rather than the growth of new. [J Refract Surg. 1996;12:370-381.1
Mechanical Stability of the Cornea After Radial Keratotomy and Photorefractive Keratectomy
Authors: Hjortdal Jesper Ø , Böhm Andreas , Kohlhaas Markus , Olsen Hanne , Lerche Ralph , Ehlers Niels , Draeger Jörg 
Published: April 2021

ABSTRACT
BACKGROUND: Corneal refractive surgical procedures alter the shape and structure of the tissue, possibly compromising its mechanical stability.
METHODS: One or both eyes of 87 subjects were studied: 26 of these 87 had been treated for myopia by excimer laser ablation and 36 by radial keratotomy; 25 without previous corneal surgery functioned as controls. Corneal topography was evaluated by TMS-I videophotokeratography before and after 180° tilting of the patient, and the pressureinduced ring-wise changes in spherical equivalent power (axial power) were calculated. Changes in corneal shape also were evaluated by computing the instantaneous radius of curvature. The intraocular pressure was measured before and after tilting by a hand-held applanation tonometer.
RESULTS: The mean intraocular pressure increased from 13.9 + 2.3 nun Hg before tilting to 30.0 ± 3.8 mm Hg during tilting. In the control eyes, the mean power of the central cornea during tilting decreased 0.187 + 0.045 diopters (D) (p<.05); in the excimer-laser-ablated eyes, 0.038 ± 0.056 D (not statistically significant); and in those treated with radial keratotomy, 0.523 ± 0.054 D (p<.01). After radial keratotomy, the cornea steepened outside the clear zone in response to pressure loading, whereas it did not change significantly in the laserablated or control eyes.
CONCLUSIONS: Pressure-induced deformation of normal and excimer laser-ablated human cornea is small, whereas radially incised corneas have significantly decreased mechanical stability. [J Refract Surg. 1996;12:459-466.]
Central Focal Interface Opacity After Laser in situ Keratomileusis
Authors: Fraenkel Graham E , Cohen Peter R , Sutton Gerard L , Lawless Michael A , Rogers Christopher M 
Published: April 2021

ABSTRACT
BACKGROUND: The acute onset of a focal central interface opacity with visual loss following LASIK has not been described in the peer reviewed literature. Non-peer reviewed reports of various inflammatory lesions have been recorded.
METHODS: We describe three cases in which an acute focal stromal interface opacification was identified within 1 week of laser in situ keratomileusis (LASDX). Each case was performed by a different surgeon on a different day, but using the same method, materials, and the Summit Apex Plus excimer laser. Immediately after surgery, all eyes were normal with good unaided vision. The appearance of the central stromal opacity was associated with acute visual deterioration. Preoperative and postoperative cycloplegic refractions, videokeratography, and postoperative slit-lamp biomicroscopy were performed. Each case was treated with intensive topical corticosteroids.
RESULTS: Each case demonstrated a central circular opacity in the interface between corneal flap and stromal bed, with associated variable stromal thinning. Resolution of the pathological process followed 2 to 4 weeks of treatment with topical corticosteroids and subsequent improvement in slitlamp biomicroscopy, corneal topography, and vision. Etiology was uncertain.
CONCLUSION: Central interface opacification is a rare but visually important inflammatory complication of LASLK. [J Refract Surg 1998;14:571-576]
Prospective Study of Photorefractive Keratectomy for Hyperopia Using an Axicon Lens and Erodible Mask
Authors: Haw Weldon W , Manche Edward E 
Published: April 2021

ABSTRACT
PURPOSE: To evaluate prospectively the longterm safety, efficacy, and visual performance following photorefractive keratectomy (PRK) for hyperopia using an erodible mask and axicon lens system.
METHODS: Eighteen eyes of 9 patients with a mean preoperative spherical equivalent refraction of +2.26 ± 0.82 D (range, +1.13 to +4.00 D) underwent PRK with the Summit Apex Plus excimer laser following manual scraping of the epithelium. Eyes were prospectively evaluated 1, 3, 6, 9, 12, 18, and 24 months following the procedure. Primary outcome variables included cycloplegic refraction and uncorrected visual acuity (UCVA). Visual performance was determined by contrast sensitivity measurements under scotopic (21 lux) and photopic (324 lux) conditions and best spectacle-corrected visual acuity (BSCVA) under scotopic, photopic, and glare conditions.
RESULTS: For 18 eyes, 98.2% of the mean preoperative spherical equivalent refraction was corrected to +0.04 ± 0.87 D (range, -1.38 to +2.00 D) at 24 months after PRK Twelve eyes (67%) were within ±0.50 D of attempted correction and 15 eyes (83%) were within ±1.00 D. Stability within ±0.50 D was achieved after 6 months. Two eyes (11%) experienced almost complete regression of the refractive effect. There was no statistically significant decrease in contrast sensitivity under scotopic or photopic conditions. (P > .05). Best spectaclecorrected visual acuity showed progressive improvement in the early postoperative period. By 24 months, 0 eyes (0%) lost 2 or more lines of BSCVA under scotopic and photopic conditions and 1 eye (5.5%) lost 2 or more lines under glare conditions. Fourteen eyes (78%) had grade 1 to 3 anterior stromal haze at 24 months which was characteristically mid-peripheral and did not adversely affect visual performance.
CONCLUSION: Photorefractive keratectomy with the the Summit Apex Plus excimer laser for low to moderate hyperopia resulted in an effective reduction of hyperopia without compromising long-term visual performance. Stability and recovery of distance uncorrected and best spectaclecorrected visual acuity took approximately 6 months. [J Refract Surg 2000;16:724-730]
Late Onset Diffuse Lamellar Keratitis Associated With an Epithelial Defect in Six Eyes
Authors: Haw Weldon W , Manche Edward E 
Published: April 2021

ABSTRACT
PURPOSE: To report six cases of late onset diffuse lamellar keratitis associated with epithelial defects 2 to 12 months following uncomplicated laser in situ keratomileusis (LASIK).
METHODS: Retrospective case series.
RESULTS: The interface inflammation and epithelial defects were treated aggressively with topical corticosteroids and topical antibiotics with complete resolution over 1 to 2 weeks. There were no complications or loss of best spectacle-corrected visual acuity. These cases illustrate new understanding in the etiology of diffuse lamellar keratitis following lamellar surgery.
CONCLUSION: Late onset diffuse lamellar keratitis in association with epithelial defects may occur following LASIK. Treatment with topical antibiotics and topical corticosteroids may result in uncomplicated, complete resolution. [J Refract Surg 2000;16:744-748]
Penetrating Keratoplasty vs. Epikeratoplasty for the Surgical Treatment of Keratoconus
Authors: Wagoner Michael D , Smith Scott D , Rademaker Wilfried J , Mahmood Muneera A 
Published: April 2021

ABSTRACT
PURPOSE: Penetrating keratoplasty and epikeratoplasty have been utilized in the surgical treatment of keratoconus. Comparison of the relative efficacy of each procedure in achieving visual outcomes has not been achieved due to limited numbers of cases and follow-up in previous series.
METHODS: All patients who underwent either penetrating keratoplasty or epikeratoplasty for keratoconus between January 1987 and December 1997, and for whom at least 24 months of postoperative follow-up data for visual acuity was documented in the medical record, were included in this retrospective, nonrandomized, sequential comparative trial. The sole criteria for outcome in each group, as well as for comparison of the two groups, was Snellen visual acuity measured at the time of each follow-up with the presenting optical aid.
RESULTS: Inclusion criteria were met for 443 eyes treated with penetrating keratoplasty and 161 eyes treated with epikeratoplasty. Mean follow-up was 4.3 years for penetrating keratoplasty and 4.5 years for epikeratoplasty. In each group, approximately 50% of the patients chose rehabilitation with optical correction with either spectacles or contact lenses and 50% chose no optical correction. Final median logMAR visual acuity for all patients, irrespective of means of visual rehabilitation, was 0.30 (20/40) for penetrating keratoplasty and 0.40 (20/50) for epikeratoplasty (P < .00005). In 209 penetrating keratoplasty and 77 epikeratoplasty eyes with optical correction, the final median logMAR visual acuity was 0.18 (20/30) for penetrating keratoplasty and 0.40 (20/50) for epikeratoplasty (P < .00005). The final median logMAR visual acuity in 234 penetrating keratoplasty and 84 epikeratoplasty eyes without optical correction was 0.48 (20/60) in both groups (P-value was not statistically significant).
CONCLUSIONS: Although penetrating keratoplasty was statistically superior to epikeratoplasty with respect to visual outcome, results with epikeratoplasty were adequate to recommend its use as a surgical alternative in cases when it is not desirable to perform penetrating keratoplasty. [J Refract Surg 2001;17:138-146]