Posters

Pulsed accelerated corneal collagen cross-linking for the treatment of keratoconus

Poster Details

First Author: S.Coutts UK

Co Author(s):    A. Barsam              

Abstract Details

Purpose:

Progression of corneal ectasia in keratoconus has successfully been arrested by the use of riboflavin and ultraviolet A (UV-A) irradiation in corneal cross-linking. The standard Dresden protocol involves a 30 minute riboflavin soak and 30 minute UV-A exposure (3mW/cm2); modification of this has led to a pulsed and accelerated protocol. Success of cross-linking is related to the availability of oxygen in the procedure. Pulsing of UV-A irradiation allows oxygen to diffuse back into the cornea and this optimised oxygen availability leads to a greater cross-linking effect with the same dose of UV-A. The purpose of this study was to evaluate the success of an accelerated and pulsed protocol in arresting keratoconus progression.

Setting:

Department of Ophthalmology, Luton and Dunstable University Hospital NHS Trust, Bedfordshire, England, UK.

Methods:

The first twenty consecutive eyes (n=20) of twenty patients with documented progression of keratoconus received the new protocol of riboflavin soak for 10minutes (epithelium off) , followed by UV-A administration over 4 minutes, pulsed for 8 minutes in total at 30mW/cm2 (1 second on, 1 second off). The topographic progression was evaluated using Pentacam (Oculus Inc) and corneal flattening was measured using KMax, the indice for steepest radius of curvature (Dioptres). Patients were evaluated for post procedure complications and Pentacam readings taken at 2, 4 and 6 months post operatively. Once topography confirmed the disease had not progressed patients were seen yearly.

Results:

Twenty eyes of twenty patients underwent accelerated and pulsed corneal cross-linking with a mean patient age of 21.2 years. Of the twenty eyes no case showed progression in keratoconus with a mean pre- operative KMax of 59.29D(+/-6.02). This KMax value reduced to 57.86D (+/- SD 6.78) at 2 months or a mean corneal flattening of -1.43D (+/- SD 2.60) and at 6 months this mean change was -2.08D (+/-SD 1.26). Visual acuity was also maintained in all except one patient.

Conclusions:

Our results show the biomechanical effect of corneal cross-linking is not negated by optimisation of the protocol variables. Reducing UV energy exposure and soak time as per an accelerated and pulsed protocol allows for quicker treatment with equal safety and efficacy profiles. With these findings the optimised protocol is now used as a standard for all cases of corneal cross-linking. FINANCIAL INTEREST: NONE