Posters

Pulsed light accelerated corneal collagen cross-linking using an 18mW/cm2 2-seconds-on 1-second-off protocol for keratoconus: three-year outcomes

Poster Details

First Author: V.Barnett UK

Co Author(s):    S. Zormpas   J. Than   A. Barsam              

Abstract Details

Purpose:

Keratoconus is an ectatic disorder affecting approximately 1 in 1000 people, resulting in progressive myopia and irregular astigmatism secondary to conical protrusion and apical thinning of the cornea. Collagen cross-linking is the gold standard treatment for progressive disease. Accelerated cross-linking protocols have shown promise in terms of generating similar outcomes to traditional protocols in shorter periods of time. We propose a novel protocol using an epithelium-off pulsed accelerated CXL regime: actual treatment time 6 minutes 40 seconds increasing to a total of 10 minutes with pulsing (2 seconds on/1 second off) at 18mW/cm2 with total energy dose of 7.2J/cm2.

Setting:

Ophthalmology Department, Luton and Dunstable University Hospital, United Kingdom

Methods:

Patients with progressive keratoconus, minimum corneal thickness ≥375μm, no further ocular comorbidities and no prior corneal surgery underwent the novel protocol. All patients underwent alcohol-assisted epithelial debridement (9mm diameter) followed by corneal soaking with dextran-free riboflavin 0.1%. Subsequent epithelium-off pulsed accelerated corneal CXL using KXL 1 UV-A source (Avedro Inc., MS, USA) with a total treatment time of 6 minutes 40 seconds, increased to 10 minutes with pulsing (2 seconds on/1 second off). Total energy dose was 7.2J/cm2. BCVA, Kmax, corneal astigmatism, and minimum corneal thickness were recorded from the pre-operative visit to 36 months post-operatively.

Results:

62 eyes of 53 patients underwent the protocol. Mean follow-up duration was 23 months. At last follow-up, mean BCVA improved from logMAR equivalent 0.26 to 0.17 (p<0.01). Mean Kmax remained stable during the study period (57.5 to 56.9D, p>0.05), as did mean corneal astigmatism (3.9 to 4.0D, p>0.05). Minimum corneal thickness reduced from 470 to 448μm (p<0.0001). One patient was excluded due to post-operative subtotal corneal melt and secondary pseudomonas microbial keratitis requiring penetrating keratoplasty.

Conclusions:

This audit demonstrates the safety and efficacy of our novel accelerated CXL protocol in stabilising progressive keratoconus. Further work with larger sample size, longer follow-up, and comparison versus gold standard Dresden protocol CXL is required to determine long-term safety and efficacy of this protocol.

Financial Disclosure:

None