Posters

Wavefront-guided photorefractive keratectomy using a high resolution aberrometer after corneal collagen cross-linking in keratoconus

Poster Details

First Author: A.Bardan UK

Co Author(s):    M. Shaheen   M. Elkateb   H. Helaly              

Abstract Details

Purpose:

To evaluate the clinical outcomes of wavefront-guided (WFG) photorefractive keratectomy (PRK) using a high definition aberrometer in keratoconus corneas at least 1 year after corneal collagen cross-linking (CXL)

Setting:

Horus Eye Center, Alexandria, Egypt

Methods:

Prospective uncontrolled interventional case series study including a total of 34 consecutive eyes of 25 patients with keratoconus previously treated with CXL. All cases underwent WFG PRK using the VISX STAR S4IR excimer laser and the iDesign system (Abbott Medical Optics). All eyes had keratoconus grade I or II according to the Amsler-Krumeich classification. Visual, refractive and ocular aberrometric outcomes were evaluated during a 12-month follow-up. Astigmatic changes were analyzed with the Alpins vector method.

Results:

A significant improvement was observed in uncorrected and corrected distance visual acuity (p<0.001). Mean efficacy and safety indices at 12 months postoperatively were 1.58�Â�±1.11 and 1.96�Â�±1.52, respectively. Manifest sphere and cylinder were reduced significantly (p<0.001), with 76.5% of eyes having a spherical equivalent within �Â�±1.00 D at 12 months postoperatively. Mean difference vector and magnitude of error were 1.06�Â�±0.92 and 0.43�Â�±0.86 D, respectively. Some corneal irregularity indices were reduced significantly with surgery (p�â�‰�¤0.005) as well as the level of ocular higher order aberrations (HOA), primary coma, and trefoil (p<0.001).

Conclusions:

Sequential WFG PRK using the iDesign system and the STAR S4IR excimer laser after CXL is an effective option to correct the spherocylindrical error and to minimize the level of HOAs in mild and moderate keratoconus if the maximum intended ablation depth does not exceed 15% of minimal corneal thickness.

Financial Disclosure:

NONE