الفهرس | Only 14 pages are availabe for public view |
Abstract Photorefractive keratectomy (PRK) has commonly been used as an effective technique for refractive surgeries and is well tolerated by the patients. In PRK, the corneal epithelium should be removed before stromal ablation. There are several methods for epithelial debridement including mechanical, chemical, rotating brush, and using Excimer laser. Previous studies demonstrated that all of these epithelial removal techniques are effective for surgical correction of refractive errors. Mechanical debridement seems to be the most common technique for epithelial debridement. Although mechanical technique is effective, it has some problems, especially for surgeons without enough experience. Using alcohol may also have some toxic effects on corneal stem cells. Increased epithelial debridement time can increase patient anxiety and increase stromal dehydration caused by evaporation. Trans-epithelial PRK removes corneal epithelium and stroma in a single step with one ablation profile. In this technique, laser removes the corneal epithelium using a preset thickness of a normal cornea epithelium (55-65 μm) based on previous reports. In theory, this technique gives a smoother corneal surface than that achieved with mechanical ablation of the epithelium. The aim of this study was to compare the outcomes of Trans PRK with those of conventional PRK with respect to the postoperative pain, healing time, visual acuity recovery and haze. This was a prospective comparative non randomized case series study conducted in private eye-laser centers, Menoufia governorate, Egypt, the study was conducted on one hundred patients (194 myopic eyes) with or without astigmatism who met the eligibility criteria after well-informed consent. Cases were divided into two groups. Each group includes 97 eyes. group 1: 50 patients who undergone Trans PRK group 2: 50 patients who undergone conventional PRK The main results of the study revealed that: There was non-significant difference between the studied groups as regarding age and sex. There was highly statistically significant difference between the different readings of visual acuity at different time measurements which was found to increase gradually from the operation till after 3 months post-operatively (0.11 versus 1.02 respectively) in Trans-PRK and (0.29 versus 0.95 respectively) in those underwent PRK operation. It was also noticed that visual acuity 3 months post-operatively was corrected more among patients underwent trans-PRK compared to PRK (1.02 versus 0.95 respectively). There was highly statistically significant difference between both groups as regarding SE readings at one month after the operation. The same finding was detected also after 3 months, the readings were significantly higher among Trans PRK patients compared to PRK ones. There was no statistical significant difference between PRK regarding to Pain level. 69 Summary There was highly statistical significant difference between Trans PRK regarding to Healing epithelium. There was statistically significant difference between both groups as regarding haze grade. Based on our result, we recommend for further studies on large geographical scale and on larger sample size to emphasize our conclusion. |