Factors associated with changes in posterior corneal surface following photorefractive keratectomy

Session Details

Session Title: Refractive
Session Date/Time: Friday 15/02/2019 | 08:30-10:00
Paper Time: 08:36
Venue: Room MC3

First Author: M.Mimouni ISRAEL
Co Author(s): A. Nemet  I. Vainer  T. Sela  I. Kaiserman        

Abstract Details

Purpose:

To identify factors associated with changes in the posterior cornea curvature following laser refractive surgery.

Setting:

Care-Vision Laser Centers, Tel-Aviv, Israel

Methods:

This retrospective study included myopic astigmatic eyes that underwent PRK between January 2013 and December 2013. The average posterior K was measured with the Sirius device at a radius of 3 millimeters from the center. The surgical induced change in the average posterior k was calculated. The correlations between change in posterior K and parameters such as preoperative central corneal thickness (CCT), refraction, Baiocchi Calossi Versaci index (BCV), ablation depth, percent tissue altered (PTA) and residual stroma bed (RSB) were analyzed.

Results:

A total of 280 eyes were included in this study. Lower CCT (r=-0.24, p<0.001), higher myopia (r=-0.34, p<0.001), increased astigmatism (r=-0.17, p<0.001), increased total BCV (r=0.13, p=0.03), decreased back BCV (r=-0.12, p=0.05), increased front BCV (r=0.16, p=0.01), increased posterior I-S ratio (r=0.16, p=0.01) and a lower RSB (r=-0.42, p<0.001) were all correlated with percentage of change in mean posterior K. A greater change in posterior K was found in females (p=0.01), smaller important optic zones of 6.0mm (p=0.02) and PTA > 20% (p<0.001). Factors that remained significant in multivariate analysis were PTA (p<0.001), CCT (p=0.001) and posterior I-S ratio (p=0.001).

Conclusions:

Preoperative CCT, posterior I-S ratio and PTA are significantly associated with changes in posterior K after PRK. Understanding of factors affecting a change in posterior cornea after refractive surgery may be important practical value for the prevention of iatrogenic keratectasia.

Financial Disclosure:

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