Refractive outcomes, corneal haze and endothelial cell loss after myopic photorefractive keratectomy in an Asian population: The Singapore Armed Forces' experience.

Abstract

This study reports outcomes of myopic photorefractive keratectomy (PRK) in a mainly ethnic Chinese population in Singapore. To assess the incidence and associations of corneal haze and endothelial cell count (ECC) loss up to 12 months after PRK. This was a retrospective case series conducted in a tertiary eye centre. A total of 158 patients (309 eyes) with a mean age of 22.1 ± 3.4 years were included. The majority was Chinese (97.4%) and male (97.4%). Mean preoperative spherical equivalent was -3.33 ± 1.15 D. Eyes were categorized based on postoperative haze severity. A multivariate analysis adjusting for age and use of intraoperative mitomycin-C (MMC), preoperative sphere and cylinder was performed. Refractive outcomes and corneal haze 3 and 12 months after PRK were assessed. ECC measurements were obtained before PRK and at variable periods postoperatively. At 12 months, overall efficacy index was 0.98, and safety index was 1.09. Eight (2.5%) eyes underwent enhancement surgery. An analysis was performed on 295 eyes that did not undergo enhancement and had complete clinical data, which demonstrated a decrease in the incidence of haze from 38.2% at 3 months to 9.3% at 12 months. Higher myopia was associated with increased haze severity at 3 months (OR, 1.36; P = .005). Higher astigmatism was associated with increased haze severity at 3 (OR, 1.65; P = .018) and 12 months (OR, 2.32; P = .015). Intraoperative MMC was not associated with haze severity or ECC loss. Myopia and astigmatism were associated with increased corneal haze severity. Intraoperative MMC did not accelerate ECC loss. Overall, PRK is effective, predictable and safe in Asian eyes.