Transepithelial vs. Epithelium-off Photorefractive Keratectomy in Myopic Patients with High Astigmatism: A Randomized Contralateral Eye Trial
Leila Babaei1 *, Alireza peyman1 , Mohsen poorazizi1
- isfahan university of medical sciences
Abstract: Abstract
Purpose: To compare clinical outcomes of transepithelial photorefractive keratectomy (t-PRK) and conventional epithelium-off PRK (PRK) in myopic patients with high astigmatism.
Methods: Method: Sixty eyes of 30 individuals aged over 20 years old with at least minus 1 diopter of
spherical and 3 diopters of cylindrical refractive error with stable refraction who were candidate
for corneal refractive surgery enrolled the study. Both eyes of each patient were randomly allocated to operate by t-PRK method as case group or PRK as contralateral control group. The astigmatic analyses through Alpin’s method compared to evaluate the outcome 6 months after surgery.
Results: Results: Both methods yielded significant improvements in visual acuity, spherical and cylindrical refractive error (P<0.001). At 6-month postoperative, cylindrical refractive error had marginally smaller magnitude in eyes treated with t-PRK (-0.51 ± 0.29) compared to PRK (-0.67 ± 0.30) (P= 0.04). The residual astigmatism was ? 0.50 diopters in 23 eyes (76 %) in the t-PRK group and 15 eyes (50%) in the PRK group. Using vector analysis, t-PRK resulted in significantly higher percentage success of astigmatic surgery (84.68 ± 8.95 in t-PRK versus 79.46 ± 10.88 in PRK, P= 0.04) and lower difference vector (DV) (0.51 ± 0.28 in t-PRK versus 0.66 ± 0.31 in PRK, P = 0.04). Additionally, a marginal statistical significance with a more favorable range was reported in the postoperative index of success of astigmatism surgery (P=0.06), absolute (P=0.08) and arithmetic (P=0.07) angles of error in the t-PRK group compared to the PRK group.
Conclusion: Conclusion: Six-months outcomes revealed that both t-PRK and PRK are essentially equivalent
in efficacy and safety in correcting eyes with high astigmatism. However, t-PRK demonstrated
more favorable astigmatism correction.
