Posters

Simultaneous combined wavefront-guided transepithelial photorefractive keratectomy and corneal collagen cross-linking for progressive keratoconus

Poster Details

First Author: D. Gore UNITED KINGDOM

Co Author(s):    B. Allan                    

Abstract Details

Purpose:

Simultaneous transepithelial photorefractive keratectomy (TransPRK) and corneal collagen cross-linking (CXL) aims to reverse visual loss attributable to irregular astigmatism in early stage keratoconus without compromise to stabilization of disease progression. Here we present interim 12-month visual results from the TransPRK/CXL trial (NCT02208089) using a commercially available tissue saving wavefront guided algorithm for TransPRK which exclusively targets dominant higher order aberrations (irregular astigmatism).

Setting:

The Refractive Surgery Service, Moorfields Eye Hospital, London

Methods:

Patients with progressive stage II-III keratoconus, LogMAR corrected distance vision acuity (CDVA) <0.00 (<6/6) and no ocular copathology were included. Aberrometry guided TransPRK (≥8mm diameter) was performed using the Schwind Amaris 750S excimer laser platform (Schwind Eye-tech Solutions, Kleinostheim, Germany). Mitomycin C was not used. Tissue ablation depth was minimised by treating dominant higher order aberrations only with no compensatory additional tissue removal to control for induced changes in sphere and cylinder. An accelerated CXL protocol was used: 10 minute soak (Vibex Rapid), 4 minutes (1.5sec pulsed) UV exposure (30mW/cm2) using an Avedro KXL UV source (Avedro, Waltham MA).

Results:

To date, 18 eyes of 18 patients have reached 12-month follow-up (total recruitment 55 patients). Mean (SD) CDVA improved from 0.27 (±0.20) LogMAR pre-operatively to 0.13 (±0.21) 12-months post treatment (p < 0.01, t-test). Mean (SD) stromal ablation depth at the cone apex was 29µm (±9µm). Two eyes lost CDVA (0.14 and 0.20 logMAR units respectively) associated with anterior stromal haze. Coma was the dominant aberration preoperatively. Significant reductions in coma and corneal asymmetry were evident in topographic comparison maps.

Conclusions:

Wavefront guided transPRK in combination with accelerated CXL reduces irregular astigmatism and results in significant gains of CDVA in patients with stage II-III keratoconus. Longer-term follow-up and comparison of results with historical control eyes treated with the same accelerated CXL protocol and no TransPRK will further quantify these visual gains and help to identify any negative effect of combined treatment on corneal shape stability.

Financial Disclosure:

NONE