Khalid F Tabbara1, Amgad A Kotb. 1. The Eye Center and The Eye Foundation for Research in Ophthalmology, Riyadh, Saudi Arabia.
Abstract
PURPOSE: To establish a grading system that helps identify high-risk individuals who may experience corneal ectasia after LASIK. DESIGN: Retrospective, comparative, interventional case series. PARTICIPANTS: One hundred forty-eight consecutive patients (148 eyes) were included in this study. Thirty-seven patients who underwent LASIK at other refractive centers experienced corneal ectasia in 1 eye after LASIK. One hundred eleven eyes of 111 patients who underwent successful LASIK during the same period were age and gender matched and served as controls. INTERVENTION: All patients underwent preoperative and postoperative topographic analysis of the cornea. The follow-up period in both groups of patients ranged from 2 to 5 years, with a mean follow-up of 3.6 years. All patients underwent LASIK for myopia (spherical equivalent, -4.00 to -8.00 diopters). MAIN OUTCOME MEASURES: Corneal keratometry, oblique cylinder, pachymetry, posterior surface elevation, difference between the inferior and superior corneal diopteric power, and posterior best sphere fit (BSF) over anterior BSF were given a grade of 1 to 3 each. An ectasia grading system was established, and the cumulative risk score was assessed. RESULTS: Patients who had a grade of 7 or less showed no evidence of corneal ectasia, whereas 16 (59%) of 27 patients who had a grade of 8 to 12 had corneal ectasia. Twenty-one (100%) of 21 patients with a grade of more than 12 had corneal ectasia after LASIK (P<0.0001). CONCLUSIONS: A risk score may help in the prediction of patients who are at risk of experiencing corneal ectasia after LASIK. A prospective clinical study is needed to assess the validity of these risk factors.
PURPOSE: To establish a grading system that helps identify high-risk individuals who may experience corneal ectasia after LASIK. DESIGN: Retrospective, comparative, interventional case series. PARTICIPANTS: One hundred forty-eight consecutive patients (148 eyes) were included in this study. Thirty-seven patients who underwent LASIK at other refractive centers experienced corneal ectasia in 1 eye after LASIK. One hundred eleven eyes of 111 patients who underwent successful LASIK during the same period were age and gender matched and served as controls. INTERVENTION: All patients underwent preoperative and postoperative topographic analysis of the cornea. The follow-up period in both groups of patients ranged from 2 to 5 years, with a mean follow-up of 3.6 years. All patients underwent LASIK for myopia (spherical equivalent, -4.00 to -8.00 diopters). MAIN OUTCOME MEASURES: Corneal keratometry, oblique cylinder, pachymetry, posterior surface elevation, difference between the inferior and superior corneal diopteric power, and posterior best sphere fit (BSF) over anterior BSF were given a grade of 1 to 3 each. An ectasia grading system was established, and the cumulative risk score was assessed. RESULTS:Patients who had a grade of 7 or less showed no evidence of corneal ectasia, whereas 16 (59%) of 27 patients who had a grade of 8 to 12 had corneal ectasia. Twenty-one (100%) of 21 patients with a grade of more than 12 had corneal ectasia after LASIK (P<0.0001). CONCLUSIONS: A risk score may help in the prediction of patients who are at risk of experiencing corneal ectasia after LASIK. A prospective clinical study is needed to assess the validity of these risk factors.
Authors: Maria A Woodward; J Bradley Randleman; Buddy Russell; Michael J Lynn; Michael A Ward; R Doyle Stulting Journal: J Cataract Refract Surg Date: 2008-03 Impact factor: 3.351