الفهرس 
Aim of the WorkOnly 14 pages are availabe for public view
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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.
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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.