ESCRS - PO255 - Deep And Irregular Demarcation Lines Following Corneal Cross Linking With Epithelial Removal By Phototheurapeutic Keratectomy

Deep And Irregular Demarcation Lines Following Corneal Cross Linking With Epithelial Removal By Phototheurapeutic Keratectomy

Published 2022 - 40th Congress of the ESCRS

Reference: PO255 | Type: Free paper | DOI: 10.82333/zmbe-6002

Authors: Canan Aslı Yıldırım* 1 , Isilay Kavadarli 2 , Vedat Kaya 3

1Dokuz Eylul University Department of Ophthalmology,Izmir,Türkiye, 2Private ophthalmology practice,Istanbul,Türkiye, 3Department of Ophthalmology,Liv Hospital, Istinye University,Istanbul,Türkiye

Purpose

To evaluate the depth of demarcation lines after corneal cross linking (CXL) with epithelial removal by phototheurapeutic keratectomy (PTK) in eyes with progressive keratoconus.

Setting

University hospital clinic

Methods

Keratoconus patients with clinical evidence of progression (i.e., increase in maximum keratometric value of at least 1 D/year, decrease in best corrected visual acuity, need for 2 or more contact lens exams within a year) and central corneal thickness ≥450 μm were recommended epithelium-off CXL surgery combined with epithelial removal by PTK. All participants underwent CXL procedure with an accelerated protocol for 10 minutes, followed by central, 8.5 mm-diameter corneal epithelial debridement by PTK. A 0.1% Riboflavin with 1.1% HPMC solution without dextran (Mediocross®M) was used for stromal saturation. 365 nm ultraviolet-A light was applied for 10 minutes at an irradiance of 9 mW/cm2, delivering a total dose of energy of 5.4 J/cm2.

Results

A total of 9 eyes of 5 keratoconus were included. Mean preoperative and postoperative best corrected visual acuities were 0,56 ± 0,16 and 0,57 ± 0,24 in Snellen lines. Mean flat and steep keratometric readings were 49,09 ± 3,92 D and 53,54 ± 4,97 D preoperatively; 47,49 ± 2,06 D and 52,04 ± 2,15 D postoperatively. Thinnest corneal pachymetric readings were 470,29 ± 16,00 µ preoperatively and 456,57 ± 24,30 µ postoperatively. The stromal demarcation lines were irregular with a depth of 189 µ to 372 µ, even in the same corneal OCT section. The stromal demarcation lines were as close as 20 µ to the posterior stromal surface in some sections.

Conclusions

The irregularity and variation in the depth of demarcation lines and patchy scarring areas in these eyes might be a result of defects in the ablated Bowman’s membrane. In cases when CXL combined with excimer laser ablation is planned, a customized approach in riboflavin concentration and/or application duration seems to be mandatory.