LASER IN-SITU KERATOMILEUSIS ASSISTED BY CORNEAL TOPOGRAPHY

Purpose: To assess whether laser in situ keratomileusis (LASIK) assist ed by corneal topography can successfully treat corneal irregularities or irregular astigmatism in patients with previous ocular surgery or ocular trauma. Setting: University Eye Hospital, Klinikum Mannheim, Ma nnheim, Germany. Methods: In a prospective clinical study, LASIK was p erformed in 23 eyes of 22 patients. Reasons for surgery were irregular astigmatism after penetrating keratoplasty or penetrating injury or c orneal irregularity after previous excimer laser surgery. Excimer abla tion was based on preoperative corneal topography data (Corneal Analys is System, EyeSys Technologies) using a proprietary algorithm (Topogra phic Assist LASIK, Chiron Vision). Follow-up was 6 months. Results: Me an preoperative uncorrected visual acuity (UCVA) was 20/80 and mean be st spectacle-corrected visual acuity (BSCVA), 20/35. Uncorrected visua l acuity improved in all but two cases. Postoperatively, mean UCVA inc reased to 20/50; mean BSCVA was unchanged. No eye lost two or more lin es of BSCVA. Postoperative topography showed less corneal irregularity in 81.3% of eyes; full correction was achieved in 19.4%. Four eyes (1 9.4%) needed re-treatment for undercorrection and three eyes (14.3%) f or regression. Conclusion: Preliminary results indicate that the conce pt of topographic-assisted LASIK is feasible. However, most eyes were undercorrected and had regression. One reason might be that corneal to pography underestimated corneal irregularity, causing significant unde rcorrection.