الفهرس 
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Abstract
The aim of this work is to evaluate the corneal haze after transepithelial PRK. This study identified risk factors for early post-PRK corneal haze and reported the refractive outcomes of PRK. The study involved one hundred eyes of patients with simple myopia and mixed myopia with astigmatism perform trans-photorefractive keratectomy (t-PRK) to correct their vision. Both age and sex were matched in both groups.
Preoperative BCVA in the patients compared of postoperative BCVA showed a statistically highly significant difference (P < 0.01). Spherical and cylindrical errors postoperatively showed marked improvement in refraction, as they showed a statistically highly significant difference (P <0.001).
Comparison of corneal haze between follow-up period one week after trans-PRK and the end of the follow-up period (6 months), showed a statistically very highly significant difference (P <0.001). This indicated that there is improvement of corneal haze by time from 1 weeks, 1 month, 3 months and 6 months (more improvement after 6 months in other studies).
Correlation coefficient (r) between preoperative VA and incidence of corneal haze showed inverse (negative) correlation as the increase in visual acuity preoperatively will decreases the incidence of corneal haze postoperatively. They were statistically highly significant negative correlation (r=-0.5129, P <0.01).
Correlation coefficient (r) between preoperative spherical error and incidence of corneal haze showed positive correlation as the increase in spherical error preoperatively will inذcrease the incidence of corneal haze postoperatively. They were statistically significant positive correlation (r= 0.3897, P <0.05). Also, correlation between preoperative cylindrical error and incidence of corneal haze showed positive correlation as the increase in cylindrical error preoperatively increase the incidence of corneal haze postoperatively. They were statistically highly significant positive correlation (r= 0.4925, P <0.01). Also, there is improvement of spherical equivalent (SE) in pre- and post-operative eyes. Comparison of pre and postoperative SE shows a statistically highly significant difference (P < 0.01).
Correlation coefficient (r) between ablation depth and incidence of corneal haze showed positive correlation as the increase in ablation depth increases the incidence of corneal haze. They were statistically highly significant positive correlation (r= 0.6428, P <0.01).