A randomised, controlled trial of corneal collagen cross-linking (CXL) for progressive keratoconus in eyes with thin corneae: two year results

Session Details

Session Title: Cross-Linking II

Session Date/Time: Tuesday 16/09/2014 | 16:30-18:00

Paper Time: 17:04

Venue: Boulevard A

First Author: : E.Chan AUSTRALIA

Co Author(s): :    C. Wittig-Silva   G. Snibson           

Abstract Details

Purpose:

To assess the safety and efficacy of corneal collagen cross-linking (CXL) for progressive keratoconus in eyes with thin corneae

Methods:

This is an unmasked, prospective, randomised, controlled trial. Inclusion criteria were eyes with keratoconus where there was documented progression over the preceding 12 months, and a corneal thickness less than 400µm. CXL was performed according to a modification of the Dresden protocol using hypotonic and isotonic riboflavin 0.1% solution instilled over 15 minutes prior to and during UVA irradiation (3mW/cm2; UV-X; IROC, Zurich, Switzerland) for 30 minutes. Corneal pachymetry was performed throughout the procedure and UVA irradiation did not commence until the corneal thickness increased above 400µm. The primary outcome measure was the change in the steepest simulated keratometry value (ΔKsteep) on Pentacam (Oculus, Wetzlar, Germany) at 12 and 24 months compared to baseline. Other outcome parameters included uncorrected (UCVA) and best spectacle corrected visual acuity (BSCVA), spherical equivalent (SEQ) on subjective refraction and endothelial cell density (ECD).

Results:

19 eyes of 16 patients were recruited and randomised to either CXL treatment or a control group. One patient (two eyes) was lost to follow-up prior to treatment and was not included in this analysis. The results of 9 eyes in the CXL group and 8 eyes in the control group are reported. At baseline, the mean Ksteep was 55.84±6.56D in the control group and 57.49±5.59D in the CXL group (p=0.589). The corneal thickness at the thinnest point was 392±25µm and 381±22µm in the control and CXL groups respectively (p=0.370). In control eyes, Ksteep increased from baseline by a mean of +0.73D (p=0.296) at 12 months and +1.42D at 24 months (p=0.017), whereas treated eyes flattened from baseline by -1.10D (p=0.049) and -1.40D (p=0.055) at 12 and 24 months respectively. The mean ΔKsteep was significantly different between the two groups at 24 months (p=0.002). There was no change in the UCVA, BSCVA, SEQ or ECD in either group. There were no treatment-related complications in the CXL group.

Conclusions:

In this study, eyes with progressive keratoconus and a corneal thickness less than 400µm were able to be treated with CXL with a modest decrease in corneal curvature after 24 months. Conversely, eyes in the control group demonstrated progression over the same period..

Financial Interest:

NONE