Koray Budak

Limbal relaxing incisions with cataract surgery.

Purpose: To evaluate the effectiveness of limbal relaxing incisions (LRIs) for correcting corneal astigmatism during cataract surgery. Setting: Cullen Eye Institute, Houston, Texas, USA. Methods: In 12 eyes of 11 patients, cataract surgery was combined with LRIs. The LRIs were made according to a modified Gills nomogram and were based on preoperative corneal astigmatism determined with standard keratometry and computerized videokeratography (EyeSys Corneal Analysis System™ Version 3.2). Results: The mean preoperative keratometric cylinder was 2.46 ± 0.81 diopters (D). At 1 month postoperatively, mean arithmetic reduction in keratometric cylinder was 1.12 ± 0.74 D, and the with‐the‐wound (WTW) change (calculated by Holladay, Cravy, Koch vector analysis formula) was ‐0.70 ± 0.44. From 1 day to 1 month postoperatively, there was 0.55 D of WTW regression with minimal change in the mean cylindrical axis. There were no overcorrections. Conclusion: Limbal relaxing incisions are a practical, simple, and forgiving approach to the correction of astigmatism during cataract surgery.

Evaluation of relationships among refractive and topographic parameters

PURPOSE To examine the relationships among several refractive and topographic parameters. SETTING Cullen Eye Institute Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA. METHODS Using computerized videokeratography (EyeSys Corneal Analysis System), 287 corneas of 150 patients were retrospectively analyzed. The Holladay Diagnostic Summary (HDS) refractive maps were used to evaluate relationships among variables of the HDS and refractive error. RESULTS Myopic spherical equivalent refraction (P = .0003) and more negative asphericity (Q-values) (P = .0119) were correlated with steeper corneas. The Q-values were less negative in eyes with moderate myopia (2.0 to 6.0 diopters [D]) than in those with hyperopia (1.0 D or greater). The Q-values below -0.3 were correlated with less favorable values for predicted corneal acuity and corneal uniformity index values. Mean corneal curvature measurements obtained by computerized videokeratography and standard keratometry showed a strong degree of correlation (P = .0001). CONCLUSION As the degree of myopia and negative asphericity increased, the corneal radius of curvature decreased. Corneal Q-values less than -0.3 were associated with reduced optical performance of the cornea.

Limbal relaxing incisions in congenital astigmatism: 6 month follow-up

Purpose: To evaluate the effectiveness of limbal relaxing incisions (LRIs) for correcting naturally occurring astigmatism. Setting: Ankara Hospital, Ankara, Turkey. Methods: This prospective analysis of the results of the first LRIs in 22 eyes of 13 patients with congenital astigmatism was done using a modified Gills nomogram and was based on preoperative refractive astigmatism determined by manifest and cycloplegic refractions. There were no adjustments based on sex or age. Results: An absolute decrease of 0.91 diopter (D) (44%) in mean astigmatism was achieved after 6 months in 22 eyes. The mean uncorrected visual acuity (logMAR) increased from 0.42 to 0.26 from preoperatively to 6 months postoperatively. No patient lost best corrected visual acuity. Most regression occurred in eyes with more than 3.50 D of astigmatism and between the first and third postoperative months. Conclusion: Limbal relaxing incisions are a practical, simple, and forgiving approach for the correction of lower degrees of astigmatism.

Comparative corneal topography and refractive variables in monozygotic and dizygotic twins

PURPOSE To investigate the role of heredity in determining corneal shape, axial length, and overall refractive error. METHODS Twenty monozygotic and 19 dizygotic twin pairs, age 12 to 73 years, were enrolled in the study. Zygosity was determined by physical similarity and by responses to questions adapted from surveys. Two twin pairs were excluded because of undetermined zygosity and one pair because of keratoconus (both siblings). Refractive error was determined by an automated refractor. Manifest refraction was also recorded, as well as cycloplegic refraction in subjects under age 18 years. Corneal topography data and manual keratometer readings were also obtained. Axial lengths were determined by A-scan ultrasound. Data were analyzed by Student t tests only in the right eye. Left-eye data were comparable for all variables. RESULTS Mean intrapair difference in refractive error (spherical equivalent) was less for monozygotic than for dizygotic twins (RE: 0.41 vs 1.53; P = .001). Mean intrapair difference in axial length was less for monozygotic twins (RE: 0.39 vs 0.76 mm; P = .031). Corneal topography data (power and meridian) in all zones (3, 5, and 7 mm) also showed smaller mean differences among monozygotic pairs than dizygotic, but the difference was statistically significant only for the 5-mm zone. In addition, most Holladay Diagnostic Summary variables that were studied did not show any statistically significant differences. CONCLUSIONS Axial length and overall refractive error have a significant genetic basis. Corneal topography data appear to have other overriding determining factors for several of the variables studied.

Repeat penetrating keratoplasty: indications and prognosis, 1995-2005

Purpose To evaluate the data of penetrating keratoplasty over a 10-year period and to compare indications and outcomes of eyes undergoing single graft with those of eyes requiring regrafting. Methods A total of 652 eyes of 613 patients required single graft (Group I). Sixty-one regrafts were performed on 53 eyes (Group II). The mean follow-up time was 23.4±21.3 months (range 6–132 months). The results were evaluated for the following criteria: primary indications, allograft reactions, graft clarity, final postoperative visual acuity, and complications leading to reduction in vision. Results The most common indication was keratoconus (228 eyes; 35.0%) in Group I, and vascularized corneal scar (12 eyes; 22.6%) in Group II. Allograft reactions occurred in 96 eyes (14.7%) in Group I, and 17 eyes (32.0%) in Group II (p=0.001). At the end of the study period, 76.4% of patients in Group I had entirely clear grafts, whereas 45.3% of patients in Group II had entirely clear grafts (p=0.000). The main causes of corneal graft failure were irreversible allograft reaction, endothelial failure, and graft infection, which were all seen in higher percentage in the regraft group. A best-corrected visual acuity of 20/100 or better was achieved in 377 eyes (57.8%) in Group I and 11 eyes (20.7%) in Group II (p=0.000). Conclusions The complications of repeated surgery may reduce final graft clarity and visual acuity; the disease process necessitating regrafting may carry a poorer prognosis for sight.

Preoperative screening of contact lens wearers before refractive surgery

PURPOSE To evaluate corneal stability, measured by computerized videokeratography (CVK) after discontinuation of contact lens wear in preoperative refractive surgery candidates. SETTING Baylor College of Medicine, Cullen Eye Institute, Houston, Texas, USA. METHODS Topographic differences were analyzed in 136 noncontact lens wearers (NCLW) and 76 contact lens wearers (CLW) (18 rigid gas-permeable contact lenses [RGPCL], 58 soft contact lenses [SCL]) using EyeSys CVK after discontinuation of SCL wear for 2 weeks and RGPCL wear for 5 weeks. RESULTS There were no differences in CVK patterns between the NCLW and the CLW groups. There were no statistically significant differences between the 2 groups in topographic symmetry, asphericity, corneal uniformity index, predicted corneal acuity, and irregular astigmatism. The dioptric range for the axial and the profile difference maps in the CLW group was slightly lower than in the NCLW group. CONCLUSIONS For patients whose manifest refraction and CVK maps were within 0.5 diopters of earlier values, discontinuation of SCL wear for 2 weeks and RGPCL wear for 5 weeks was adequate for the cornea to return to its baseline topographic state.

Against-the-rule (ATR) astigmatism as a predicting factor for the outcome of amblyopia treatment

PURPOSE To evaluate whether with-the-rule (WTR) or against-the-rule (ATR) astigmatism influences the treatment outcome of anisometropic amblyopia. DESIGN A cohort study. METHODS Retrospective study of patients with unilateral amblyopia due to anisometropia without strabismus. Ninety-eight patients with simple, compound, mixed, oblique myopic, and hyperopic astigmatism were divided into seven groups based on the type of astigmatism. The groups were reviewed as to the amount of anisometropia, duration of occlusion, and best-corrected visual acuity (BCVA) before and after treatment. RESULTS There was statistically significant longer duration of occlusion and less lines gain of BCVA among patients with hyperopic ATR astigmatism compared with patients with hyperopic WTR astigmatism (P =.0143 and P =.0000, respectively) and myopic ATR patients compared with myopic WTR patients (P =.0392 and P =.0192, respectively). For the same parameters, group differences were also statistically significant when all hyperopic or myopic simple/compound/mixed ATR patients were compared with all hyperopic or myopic simple/compound/mixed WTR patients (P =.0015 and P =.0000, respectively). CONCLUSION The outcome of amblyopia treatment seems to be less favorable in patients with either hyperopic or myopic ATR astigmatism. Near vision impairment may be more amblyogenic than distance vision impairment during visual development.

Corneal Topographic Changes Induced by Excision of Perilimbal Lesions

BACKGROUND AND OBJECTIVES To evaluate corneal topographic changes induced by excision of two pterygia and a perilimbal dermoid. MATERIAL AND METHODS Using the EyeSys Corneal Analysis System, we retrospectively analyzed the changes in astigmatism, mean central corneal power, and other topographic parameters of three corneas before and after surgical removal of two pterygia and a perilimbal dermoid. RESULTS Marked corneal steepening occurred along the preoperative flat meridian after the excision of the pterygia and dermoid cyst. For each patient, surgery increased the mean central corneal curvature and decreased total astigmatism. CONCLUSION Surgical excision can ameliorate abnormal corneal topographic changes produced by limbal lesions.

Results of Therapeutic Penetrating Keratoplasty

PurposeBy a retrospective study of patients in the Ankara Hospital Eye Clinic, to determine the anatomical and visual results of therapeutic penetrating keratoplasty (PK) and its role in the management of corneal disease.MethodsTherapeutic PK was performed in 36 patients (37 eyes) who had corneal perforation due to corneal disease (23 eyes) or eyes in which perforation was imminent (14 eyes). Initial indications for grafting were nonperforated descemetocele without inflammation (six eyes, 16.2%); nonperforated bacterial corneal ulcer (five eyes, 13.5%); nonperforated herpetic keratitis with active stromal inflammation (two eyes, 5.4%); acanthamoeba keratitis (one eye, 2.7%); perforation due to herpetic keratitis (13 eyes, 35.2%); perforation due to persistent epithelial defect (8 eyes, 21.6%); or perforation due to bacterial corneal ulcer (two eyes; 5.4%). The results were evaluated for each of the following criteria: anatomical integrity of the eye, cure of the disease, complications, graft clarity, and visual acuity.ResultsAnatomical integrity was achieved in 21 of the 23 eyes (91.3%) perforated from corneal disease. Therapeutic PK cured the disease in all bacterial keratitis cases. The proportion of clear grafts was 60.9% in the 23 eyes perforated from corneal disease, and 57.1% in the 14 eyes in which perforation was imminent. Fifteen eyes (40.5%) obtained a final visual acuity of 20/100 or better; five of these eyes were not yet perforated before the PK.ConclusionsTherapeutic PK is effective in the management of the eye with active uncontrolled infection or perforation from corneal disease. Approximately half of our patients maintained a clear graft at the last visit. Without therapeutic surgery, these eyes would have been lost.

Hemorrhagic descemet’s membrane detachment after viscocanalostomy

We report a case of hemorrhagic detachment of Descemets membrane after viscocanalostomy. A 60-year-old man with pseudoexfoliative glaucoma had an uneventful viscocanalostomy in the right eye. On the first postoperative day, a 5.0 mm x 5.0 mm Descemets membrane detachment was present in the superior nasal quadrant. The space between Descemets membrane and the stroma was filled with a hemorrhage. The hemorrhage resorbed by 6 months postoperatively, and Descemets membrane completely reattached without surgical manipulation. The final visual acuity dropped from 20/40 to 20/100, final intraocular pressure was 20 mm Hg with 1 medication, and a paracentral fibrinoid scar persisted 18 months after surgery. Hemorrhagic detachment of Descemets membrane can cause visual acuity deterioration and should be recognized as a rare complication of viscocanalostomy.