Visual outcomes of topography-guided photorefractive keratectomy for treatment of patients with irregular cornea

Background
Irregular corneal astigmatism has caused a challenge to the refractive surgeons for a long time. Conventional laser ablation is usually not useful in treatment of corneal irregular astigmatism. Advanced topography-guided ablation which deals with the corneal irregularity has shown good results in the past few years.
Aim
To evaluate the efficiency of the topography-guided photorefractive keratectomy (PRK) for the treatment of irregular corneas with respect to the visual acuity and quality.
Settings
A prospective interventional case series study was performed at El Noor Ophthalmology Center from March 2017 to March 2018.
Patients and methods
This study included 20 consecutive eyes of 12 patients with irregular cornea who were deemed candidates for PRK correction. All patients underwent advanced topography-guided PRK. Visual acuity and refractive errors were assessed. Topographic examination with asphericity and regularity were evaluated using Pentacam.
Results
At 3 months, the mean uncorrected visual acuity improved from preoperative 0.13±0.12 (Decimal) (range: 0.05–0.5) to 0.79±0.12 at 3 months postoperatively (Decimal) (range: 0.6–0.9). The refractive error improved from preoperative sphere of −3.1±1.7 D (range: −5.75 to +3.00 D) to −0.03±0.36 D (range: −0.25 to +1.25 D) at 3 months postoperatively and from preoperative cylinder of −1.32±1.1 D (range: −4.5 to −0.5 D) to −0.28±0.4 D (range: −1.75 to 0.00 D) at 3 months postoperatively. Corneal asphericity, as measured by the Q value, improved from 0.34±0.31 preoperatively to −0.45±0.28 at 3 months postoperatively. Index of surface variance showed a decrease from 25.2±12.3 to 20.4±3.8.
Conclusion
Advanced topography-guided PRK using OCuLink is a good method in the treatment of irregular cornea owing to different reasons, with improvement of both visual acuity and quality.