Purpose: To examine the result of photorefractive keratectomy (PRK) with the next generation of flying spot excimer laser for the treatment of myopic refractive errors.
Patients and methods: During the study 164 eyes of 98 patients were assessed. The average age was 29.4 +/- 4.62 years. The myopic eyes were divided into 3 groups: in Group 1. (n = 115 eyes) the eyes between -1.0 D and -6.0 D were evaluated, in this group the preoperative average refraction was -3.43 +/- 1.2 D (SE = spherical equivalent); in Group 2. (n = 31 eyes) the eyes between -6.1 D and -9.0 D were evaluated; the preoperative average refraction was -7.26 +/- 2.4 D (SE). In Group 3. (n = 18 eyes) eyes above -9.0 D were examined; in Group 3. the average preoperative refraction was -10.22 +/- 3.4 D (SE) Follow-up is 6 months. PRK treatments were carried out with the Zeiss Meditec MEL 80 G-Scan flying spot excimer laser, which was operated with a 0.7 mm beam diameter and 250 Hz frequency.
Results: In Group 1. The preoperative correction decreased to -0.14 D (SE); in 71% of the treated eyes uncorrected visual acuity (UCVA) was 1.0; in 24% of the eyes UCVA improved to 1.2. Best corrected visual acuity (BCVA) was unchanged in 65% of the eyes; while in 34 improved (in 24% it improved by more than 2) Snellen lines. In Group 2. the preoperative correction decreased to -0.13 +/- 0.01 D (SE); 67% had 1.0 and 8% had a 1.2 UCVA. BCVA was unchanged in 92% in Group 2.; in 8% BCVA increased by 1 or 2 Snellen lines. In Group 3., the preoperative correction decreased to -0.44 +/- 0.2 D (SE); 96% of the eyes had a 0.8 UCVA; BCVA did not change in 75% of the eyes, 25% of the eyes gained 1 Snellen line.
Conclusions: Myopic PRK treatments with the 3rd generation of excimer laser were effective and safe. Regarding BCVA, best results were obtained in the low and medium myopia groups.