Factors Predicting the Need for Re-treatment After Laser Refractive Surgery in Patients With Mixed Astigmatism.

PURPOSE: To identify risk factors that increase the likelihood of re-treatment following refractive surgery in patients with mixed astigmatism. METHODS: This was a retrospective study including patients who underwent either laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) between 2000 and 2019 and had mixed astigmatism (spherical error of +0.50 D or greater and spherical equivalent of less than 0.00 diopters [D]). Patients were divided into two groups according to whether they underwent re-treatments during the study period. RESULTS: Overall, 785 eyes (785 patients) were included. In total, 5.2% of the eyes (n = 41) underwent re-treatment. The re-treatment group was more likely to have preoperative high astigmatism (80.5% vs 48.3%, P < .001), moderate to high hyperopia (36.6% vs 22.3%, P = .035), and to have undergone surgery earlier during the study period (P < .001). They were also more likely to have undergone surgery using the Wave-Light EX200 rather than the EX500 laser platform (Alcon Laboratories, Inc) (P < .001), have a treated optical zone of 6 mm rather than 6.5 mm (P < .001 for both), and their maximum ablation depth was greater (P < .001). There was no difference between the re-treatment and control groups regarding procedure type (PRK vs LASIK). Binary logistic regression found preoperative high astigmatism (odds ratio = 3.97, P < .001) and the type of laser platform used (EX200, odds ratio = 7.78, P < .001) as the only independent factors associated with re-treatment. CONCLUSIONS: Re-treatment rates following correction of mixed astigmatism were 5.2% over 20 years. Use of a sixth-generation laser platform significantly reduced the risk of re-treatment. Presence of high astigmatism is a significant risk factor for re-treatment. There was no difference in retreatment risk between PRK and LASIK. [J Refract Surg. 2024;40(2):e73-e78.].

Evolving surgical techniques of and indications for corneal transplantation in Ontario from 2000 to 2009.

OBJECTIVE: To determine the changes in the leading indications for and the preferred surgical techniques of corneal transplantation in Ontario over a 9-year period. DESIGN: Retrospective review of Eye Bank of Canada (Ontario Division) records. PARTICIPANTS: Recipients of corneal transplants performed in Ontario between 2000 and 2009, totaling 6240 patients. METHODS: Records of all corneal tissues sent for transplantation in Ontario by the Eye Bank of Canada (Ontario Division) from July 1 2000 to June 30 2009 were reviewed. The records consist of recipient information forms completed by surgeons at the time of corneal transplant surgery. Of the 8186 available recipient information forms, 7755 (94.7%) were sufficiently complete to meet the inclusion criteria. RESULTS: The leading indications for corneal transplantation were pseudophakic corneal edema (28.3%), regraft (21.5%), Fuchs dystrophy (16.6%), and anterior keratoconus (13.8%). Beginning in 2006, there has been a shift in the proportion of corneal transplants performed using Descemet's stripping automated endothelial keratoplasty (DSAEK) and deep anterior lamellar keratoplasty, from 2.4% to 36.1% of all corneal transplants. Concomitantly, DSAEK has replaced penetrating keratoplasty (PKP) as the technique of choice when corneal transplantation is indicated for Fuchs' dystrophy (139 DSAEKs vs. 68 PKPs in 2009) and for pseudophakic corneal edema (118 DSAEKs vs. 115 PKPs in 2009). CONCLUSION: The indications for PKP in this study agree with the North American literature. In recent years, partial-thickness transplants have gained favor over PKP for select indications in Ontario. These changes reflect the future direction of corneal transplantation and will have implications on the supply of and demand for tissues.