Treatment of Keratoconus by Topography-guided Customized Photorefractive Keratectomy: Two-year Follow-up Study

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Abstract
Purpose: To evaluate the outcome of treatment of mild to moderate keratoconus with photorefractive keratectomy (PRK) and computed videokeratography for customized ablation of the superficial corneal layers. Methods: Eighteen nonconsecutive patients with bilateral keratoconus (Krumeich classification, grade 2) were examined. Both eyes were treated in 7 patients and 1 eye in 11 patients. Eight contralateral eyes served as controls. Photorefractive keratectomy was performed with the Zeiss MEL 70 excimer laser using the topographically supported customized ablation program. We evaluated changes in keratoconus topography data at 6 (25 eyes), 12 (25 eyes), and 24 (22 eyes) months after treatment (mean follow-up: 22.56±3.97 months) and versus control eyes. Changes in visual acuity and manifest refraction (spherical equivalent and cylindrical component) were also evaluated during follow-up. Results: The mean keratoconus index, keratoconus severity index, keratoconus apex, keratoconus predictor index, opposite sector index, and differential sector index were significantly lower (all P <.0001) 24 months after treatment versus baseline data. Keratoconus topography parameters were significantly worse in control eyes 24 months after study onset versus baseline. Mean uncorrected visual acuity ( P <.0001) and best spectacle-corrected visual acuity ( P <.05) were significantly increased 24 months after surgery. Conclusions: Customized photorefractive surgery improved videokeratography indices and clinical data in patients affected by grade 2 keratoconus. [ J Refract Surg . 2008;24:145–149.]