CORNEAL HAZE AFTER ACCELERATED CXL AND COMBINED CXL WITH TOPO-GUIDED PRK FOR PROGRESSIVE KERATOCONUS: A SCHEIMPFLUG DENSITOMETRY COMPARISON

Published 2022 - 26th ESCRS Winter Meeting

Reference: P123 | Type: Abstracts | DOI: 10.82333/zd5q-gz09

Authors: Sara Neto Geada Batista* ¹ , Raquel Félix ¹ , Inês Barata ² , João Gil ³ , Esmeralda Costa ³ , Andreia Rosa ³ , Cristina Tavares ¹ , Maria João Quadrado ³ , Joaquim Murta ³

¹Ophthalmology,Centro Hospitalar e Universitário de Coimbra,Coimbra,Portugal, ²University Clinic of Ophthalmology,Faculty of Medicine, University of Coimbra (FMUC),Coimbra,Portugal;.,Clinical Academic Center of Coimbra (CACC),Coimbra,Portugal, ³Ophthalmology,Centro Hospitalar e Universitário de Coimbra,Coimbra,Portugal;University Clinic of Ophthalmology,Faculty of Medicine, University of Coimbra (FMUC),Coimbra,Portugal;.,Clinical Academic Center of Coimbra (CACC),Coimbra,Portugal

Purpose

To compare corneal haze measured by corneal densitometry after corneal collagen crosslinking (CXL) alone and after combined CXL and topography-guided excimer laser ablation using photorefractive keratectomy (PRK) in the management of keratoconus.

Setting

Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), Coimbra, Portugal

Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal

University Clinic of Ophthalmology, Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal

Methods

Retrospective, cross-sectional study of consecutive patients with documented progressive keratoconus that underwent either CXL (Group 1) or combined CXL and PRK (Group 2). The CXL procedure consisted of 10 min soak with 0.1% riboflavin followed by irradiation with UV-A light using 10 mW/cm² for 10 min (total dose 6 J/cm²). In the combined treatment group, patients performed a partial topo-guided PRK, before the same accelerated CXL protocol. Mitomycin C 0.02% for 20 seconds was used in these patients. Preoperative and postoperative corneal densitometry measurements were collected from the Scheimpflug-based scanning device Pentacam® (Oculus GmBH, Wetzlar, Germany), and were obtained from the anterior (120 μm), posterior (60 μm) and intermediate layers and in concentrical zones encompassing the 0 to 2, 2 to 6, and 6 to 10 central millimeters (mm). Postoperative measurements were obtained within the first year after surgery.

Results

The study enrolled 38 eyes from 36 patients. CXL alone was applied on 18 eyes from 17 patients (47.37%), mean age 23.29±4.86 years at baseline and mean postoperative follow-up 7.17±3.43 months, while the remaining 20 eyes from 19 patients (52.63%), mean age 28.95±7.76 and mean follow-up 7.10±2.61, underwent CXL combined with PRK. A slight increase in the mean total densitometry was noted in both Group 1 (from 15.08±1.65 to 15.83±2.39, p=0.29) and Group 2 (from 16.40±1.95 to 17.09±1.94, p=0.18). A small, statistically significant, increase in densitometry was noted in the anterior 120 μm of Group 2 (p=0.03) but not in Group 1 (p=0.29). No significant differences were noted in the increase in densitometry in the medium and posterior layers in both Group 1 and 2. In the anterior (120 μm) layer, there was a significant increase in densitometry in the 0 to 2 mm zone in Group 2 (p<0.01) but not Group 1 (p=0.07). Comparing zones 2 to 6 mm and 6 to 10 mm in the anterior cornea, there were no statistically significant differences in neither Group 1 nor Group 2.

Conclusion

Corneal haze, measured by total corneal densitometry using a Scheimpflug imaging device, was not significantly different between both treatments. A significant increase was noted when observing the anterior cornea in patients that performed CXL combined with PRK, but not CXL alone. For CXL and PRK patients, this increase in anterior densitometry was particularly noted in the central 2 mm of the cornea.