الفهرس 
I. INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 82 |  |  |
| | | from | 82 | | |
Abstract
Refractive surgery is intended to change the shape of the anterior surface of the cornea, thus changing its refractive power. There are many advantages of flap creation with a femtosecond laser and Trans epithelial PRK. The incidence of complications like button-hole, epithelial abrasion, short flap, free cap, blade marks, and irregular cut are reduced with femtosecond lasers. There are greater options in flap diameter, flap thickness, side cut angle, hinge position and hinge length. There are no moving parts as in a microkeratome. The flap safety and flap thickness predictability are increased. The femtosecond lasers have the capability to cut thinner flaps. They cut planar flaps, in contrast with the meniscus-shaped flaps obtained with a mechanical microkeratome.
This study aims to Compare between the refractive results between SMILE, femto LASIK and trans epithelial PRK and To detect the most safe method with less complications in treating myopia.
The study was carried out on 90 eyes of 45 patients.
Patients were excluded from this study if they had:
• History of previous refractive surgery.
• Any ocular disease except for refractive error.
• Irregular astigmatism.
• Corneal disease or scars.
• History of corneal or intraocular surgery.
• History of glaucoma
• History of retinal detachment.
• Abnormal iris.
• Pupil deformation.
• Macular degeneration or retinopathy.
• Neuro-ophthalmic diseases.
Patients were subjected to ophthalmic examination including visual acuity, anterior segment examination and fundus examination.
Collected data were subjected to statistical analysis and the following results were obtained:
This prospective study included patients with Myopia with/without astigmatism were allocated to SMILE, femto LASIK or trans PRK with 30 eyes in each group. The age and sex showed no significant difference between the 3 groups. With no significant change in Pentacam, Topography and pachymetry and K readings studies up to one year follow up.
Regarding SMILE group in our study, there was a decrease in postoperative UCVA compared to preoperative BCVA after 1 week with a mean value of 0.86 ± 0.13, with loss of 2 lines in 28 (93%) eyes Starting to increase again after 1 month with mean value of 0.98 ± 0.04, with no loss of lines and no significant change up to 1 year.
Regarding in femto LASIK group according to our study, the postoperative UCVA was the same as preoperative BCVA after 1 week with mean 0.98 ± 0.05, with no loss of any line with no significant change up to 1 year.
Trans PRK group showed a decrease in postoperative UCVA compared to preoperative BCVA after 1 week with a mean value of 0.92 ± 0.11, with loss of 1 line in 30 (100 %) eyes Starting to increase again after 1 month with mean value of 0.99 ± 0.03, with no loss of lines and no significant change up to 1 year. With a slight delay in visual recovery as time passed similar to that of SMILE.
The preoperative mean spherical equivalent in SMILE group was -6.40±1.57D (range: -1.0 to -9.00 D) and -4.15±1.53D (range: -1.0 to -9.00 D) in femto LASIK group and _5.24 ± 1.30D(range: -1.0 to -9.00 D) in trans PRK group with no statistically signifivant difference between 3 groups (p=0.063). The postoperative mean spherical equivalent after 1 year in SMILE group was -0.10±0.16D and -0.04±0.09D in femto LASIK group and -0.21 ± 0.41 in trans PRK group with no statistically significant difference between 3 groups (p=0.053)
In our study, SMILE group showed 4 eyes recorded with Superficial punctate keratitis (SPK) in both eyes which improved after 1 month while in femto LASIK group, 4 eyes recorded with Interphase keratitis. 2 eyes improved after 1 week. The other 2 eyes cured after 1 month. Two eyes with haze recorded after 1 week in trans PRK group which was not noticed after 3 months.
With no risk of flap displacement, SMILE and trans PRK are better procedures for those who are involved in contact sports and combative professions like army, etc. where they may be chances of trauma.
SMILE and trans PRK are also faster to perform than femto LASIK as the patient bed stays under one laser machine only.
In the evolution of refractive laser techniques, we surgeons have always longed for a time when closed intra corneal surgery would come to the front, avoiding the need to disturb the corneal surface and creating a flap. SMILE and trans PRK are steps in the right direction which has made the eye power reduction procedure safer and more efficient with promising results.
Although there was no similar studies done comparing between the 3 groups, this study had some limitations. The study had a relatively small sample size. Larger studies are needed to validate the findings with longer follow up time to be waited for.