CONTRAST SENSITIVITY CHANGES AFTER LASIK AND PHAKIC IOLS IN MODERATE TO HIGH MYOPIA

Mansour Hassan Ahmed, Mahmoud Naguib Afifi, Hazem Effat Haroun, Amal Ahmad Elgohary and Takadom Ahmed Ibrahim*

ABSTRACT

Background: LASIK; a laser in situ keratomileusis is one of the most frequently performed ophthalmic procedures world-wide. The aim of the present study is To compare the postoperative contrast sensitivity function between LASIK, posterior chamber phakic IOL (ICL) and iris-fixated anterior chamber phakic IOL (phakic Iris Claw) surgeries in moderate to high myopic eyes. Methods: A prospective randomized comparative study on 37 patients (60 eyes) with moderate to high myopia. The patients were divided into 3 groups: Group A; included twenty eyes of fifteen patients that underwent LASIK. Minimum corneal thickness is 500 μm. Group B: included twenty eyes of eleven patients underwent ICL implantation, horizontal White to white diameter is 11mm or more. Group C: included twenty eyes of eleven patients underwent phakic Iris Claw implantation, anterior chamber depth (ACD) 2.8 or more. Assessment of visual acuity (uncorrected and best corrected) and contrast sensitivity function using Vistech contrast sensitivity chart were done for all groups preoperatively and after one month and three months postoperatively. Results: After one month postoperatively the VA both UCVA and BCVA were greatly improved with correction of refraction in all groups. The contrast sensitivity functions significantly improved at all spatial frequencies (1.5, 3, 6, 12, and18 cycle per degree [c/d]) in phakic Iris Claw group. It improved in ICL group but did not reach significant levels. LASIK group showed contrast sensitivity improvement at (1.5, 3, 6 and 12c/d) that reach significant value at (3&12 c/d) slight depression was observed at spatial frequency 18 c/d. After three months postoperatively, more improvement in CS thresholds were found in all surgery groups. The LASIK group showed normalization of CS threshold at spatial frequency18 c/d. Conclusion: the study affirms the better contrast results after refractive surgery. Three months after LASIK, ICL and iris claw surgeries are enough time for recovery of contrast sensitivity. Phakic iris claw and ICL are valuable surgical correction especially with high refractive errors.

Keywords: contrast sensitivity, LASIK, ICL, Phakic iris claw, myopia, refractive surgery.