Small optical zones with aspheric profiles in laser refractive surgery for myopia: A surgical outcome and patient satisfaction study

Purpose: To assess the outcomes of small optical zone (OZ) ablations used in conjunction with largetransition zones (TZ) and a highly aspheric treatment profile.Methods: Interventional case series of 39 consecutive patients with myopia or myopic astigmatism.Patient data included pre and postoperative refraction and visual acuities, laser treatment settings andpre and postoperative corneal topography as well as questionnaire responses about the use of glassesand the quality of vision postoperatively.Results: The mean preoperative spherical equivalent was −4.50 ± 2.11 dioptres (D) and the mean OZ andTZ diameters were 4.5 ± 0.5 mm and 8.1 ± 0.4 mm, respectively. The mean patient age was 40.7 ± 10.4years. Manifest spherical refraction was within ±0.5 D in 87% of patients (±1.0 D in 99%) and cylindricalrefraction within 0.5 D in 79% (≤1.0 D in 95%). The need to wear distance glasses postoperativelywas associated with dissatisfaction with the quality of daytime vision (p = 0.05) and unhappiness withnight vision was associated with symptoms of halos (p = 0.03) and starbursts (p = 0.02). The proportionof patients reporting symptoms of dysphotopsias included: ghosting 0%; glare 2%; halos 10%; and starbursts15%. There was a significant difference in the measured mean effective OZ diameter (4.8 ± 0.3 mm)compared to the mean programmed OZ (4.5 ± 0.5 mm, p = 0.00).Conclusions: Small ablation zones, when used in conjunction with a large diameter TZ, do not lead to agreater incidence of unwanted visual phenomena over that reported by many studies with larger OZs