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Customised topography-guided corneal cross-linking (CXL) for progressive keratoconus: interim analysis

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First Author: S.Koay UK

Co Author(s):    M. Mason   M. Leucci   V. Anand   B. Allan   D. Gore        

Abstract Details

Purpose:

CXL is the gold-standard treatment to halt disease progression in keratoconus and prevent further deterioration of vision. Two-thirds of patients undergoing CXL already have impaired vision due to irregular astigmatism. Customised CXL is a new iteration of CXL in which a bespoke treatment pattern based on pre-operative tomography is applied to the cornea. This aims to reduce surface shape irregularities, thereby improving corrected vision. The primary objective of this study is to investigate visual outcome in patients with progressive keratoconus treated with customised CXL.

Setting:

Department of Cornea and External Diseases, Moorfields Eye Hospital, UK

Methods:

Patients with progressive stage I-III keratoconus and CDVA < 0.00 logMAR were eligible for the study. Manifest refraction, logMAR visual acuity and tomography were collected at baseline, 6, 12 and 24 months. Following mechanical removal of the corneal epithelium, 0.1% riboflavin drops were instilled every 2 minutes for 10 minutes. UVA irradiation was applied in three concentric circles at an irradiance of 30 mW/cm2, pulsed every 1.5 seconds. The largest (9 mm diameter, 5.4 J/cm2) was centered on the pupil, with two smaller zones (4 mm, 10.5 J/cm2 & 6mm, 8.5 J/cm2 ) centered on the maximum anterior tangential curvature.

Results:

Outcomes from 46 eyes of 46 patients with a mean age of 28.1 (± 6.3) years were available. CDVA improved from 0.17 ± 0.20 logMAR preoperatively to 0.08 ± 0.12 logMAR at 6 months. 64% of eyes gained and 7% lost 1 line or more of CDVA. Kmax improved from 56.3 ± 6.8 D at baseline to 55.4 ± 6.4 D at 6 months. No eye showed progression of keratoconus at 6 months. The higher total UVA irradiation did not have an adverse effect on endothelial cell counts or corneal clarity at 6 months. No cases of infective keratitis were recorded.

Conclusions:

Interim analysis shows CXL irradiation can be customized to selectively improve corneal shape and corrected acuity. Data collection is on-going, and will allow us to determine if these results are sustained at 12 and 24 months.

Financial Disclosure:

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