Visual Outcomes in Patients with Mixed Astigmatism after Photorefractive Keratectomies with Different Ablation Zones: A Single-center Study from Saudi Arabia.

Background: Studies from Saudi Arabia regarding the use of photorefractive keratectomies (PRK) and the optimum optical zones in the treatment of adults with mixed astigmatism are lacking. Objective: To determine the outcome of PRK treatment in adult patients with mixed astigmatism and the difference in efficacy between different optical zones sizes. Methods: This retrospective study included consecutive patients with mixed astigmatism who underwent PRK at an ophthalmology clinic in Dammam, Saudi Arabia, between January 2016 and December 2019. Examination of patients included uncorrected distal visual acuity and corrected distal visual acuity. All surgeries were conducted by a single surgeon using the standard PRK technique with different optical zones: ≤6.5 mm and >6.5 mm (i.e., 7 mm and 7.5 mm). Patients were followed up monthly for 3 months. Results: This study included a total of 65 eyes of 36 consecutive patients who underwent the PRK procedure during the study period. In the Snellen chart assessment, there was a steady increase in the number of patients whose postoperative uncorrected visual acuity was within 1 line of the preoperative corrected visual acuity. In terms of the efficacy of different optical zones, the difference between both groups (i.e., the 6.5 mm and >6.5 mm groups) in each of the three follow-ups was statistically insignificant (first follow-up, P = 0.59; second follow-up, P = 0.39; third follow-up, P = 0.28). Conclusion: This study demonstrates that the optical zone ranging from 6.5 mm to 7.5 mm yields comparable results.