Posters

Should we routinely obtain baseline corneal tomographic indices for the assessment of keratoconus on the day of corneal collagen cross-linking (CXL) surgery?

Poster Details

First Author: S.Khan UK

Co Author(s): P. Jaycock                    

Abstract Details

Purpose:

The aim of the study was to determine whether tomographic indices recorded in clinic, when patients are listed for corneal cross-linking surgery, were representative of values obtained on the day of surgery and to consider the potential impact on outcome measurements of CXL procedures.

Setting:

Bristol Eye Hospital, UK.

Methods:

A retrospective case note review was completed for 204 patients undergoing CXL for progressive keratoconus between 2015-2018. Patients were treated with a continuous wave epithelium off accelerated CXL (irradiance of 9 mW/cm2, 10 minutes) protocol using the Avedro KXL device.   Only patients who had Pentacam scans on the day of surgery, in addition to the day of initial listing for CXL, were included. All pachymetric and tomographic indices were extracted from Pentacam software. GraphPad ® software was used for all statistical analyses.

Results:

204 patients with 1 year follow-up data had Pentacam scans performed on the day of listing for CXL and had Pentacam scans performed on the day of CXL surgery. The average K max on the day of surgery was 59.00D compared to 58.60D at the day of initial listing. The average K mean on the day of surgery was 48.60D on the day of surgery compared to 48.25D at the day of initial listing.

Conclusions:

There was a significant difference between the values for average K max, K2 and K mean obtained at initial listing compared to Pentacam values obtained on the day of surgery, p<0.0001. Keratoconus can further progress from the time of listing until the day of CXL surgery. Pre-operative baseline Pentacam scans performed before the day of CXL surgery may lead to an underestimation of the success of the CXL procedure, which is often defined by strict criteria such as, change in absolute K max from pre-CXL values of ≤1.00 D.

Financial Disclosure:

None