The popularity of refractive surgery to correct ametropia is increasing, to become among the most commonly performed procedures in medicine. PRK was the first type of surface ablation procedure (refractive eye surgery) used a laser rather than a blade to remove the corneal tissue.
Removing of the epithelium in PRK was performed by several techniques including: conventional (mechanical, chemical) or trans-epithelial PRK. Single-step trans-PRK using Amaris excimer laser is a new treatment in which the epithelial removal is using a population-based epithelial profile; this type combines the epithelial and the stromal laser ablation in one step.
Many patients complain of halo, glare and blurred vision at night after successful corneal refractive surgery . High order aberrations and changes in contrast sensitivity are expected to be a causes of their complains. Wave-front technology has been developed enough in the last years to have an accurate measurements, diagnoses and treatment of HOAs.