Excimer laser treatment of hyperopia with a 9-mm ablation zone

Purpose. To develop an ablation algorithm for hyperopia that results in greater precision, less regression and better visual acuity than previous excimer strategies. Methods. A Nidek EC 5000 laser with a 5.5-mm optical zone (O.Z.) and a 3.5-mm peripheral blending zone was used, making for a total zone diameter of 9.0 mm. The central corneal remains unablated. The algorithm provides for smooth blending transitions between the ablated zone and both the untreated central and peripheral areas. The unit, working at 46 Hz, utilizes a rotating scanning slit. 18 eyes of 14 patients (26-51 years old) were treated for a mean hyperopia of +4.36 ± 2.32 D. Minimum follow-up time was 6 months. No topical corticosteroids were given postoperatively. Emmetropia was not always aimed at. Results. At 1 month postoperatively, 44.4% of the eyes were within ±0.50 D of intended correction, 38.8% within ±1.0 D, and 16.6% within 2.0 D. At 3 months the corresponding figures were 38.8%, 44.4% and 16.6%, and a 6 months 33.3%, 38.8% and 27.2%. Mean regression for the whole group was 1.8 D by 6 months. Recovery of best-corrected visual acuity (BCVA) was achieved by day 2 in 17 of the 18 eyes. No Snellen lines were lost in any eye. Maximum peripheral haze was 1+. Conclusions. The results indicate that this new algorithm, with its very large O.Z., leads to less regression and faster recovery of BCVA than previously reported for excimer treatment of hyperopia.