Posters

Evaluation of astigmatism and coma axis coincidence in determination of six month visual and refractive results for intrastromal corneal ring segments for keratoconus

Poster Details

First Author: P.Cardoso PORTUGAL

Co Author(s):    I. Lains   M. Rego   J. Gil   A. Rosa   M. Quadrado   J. Murta

Abstract Details

Purpose:

To analyze the visual and refractive outcomes of keratoconic (Kc) eyes submitted to intrastromal corneal ring segments (ICRS) implantation, according to the preoperative coincidence of flattest topographic meridian and coma axis.

Setting:

Department of Ophthalmology, Centro Hospitalar e Universitário de Coimbra, Portugal

Methods:

Retrospective study of Kc eyes implanted with ICRS (Keraring®; Mediphacos) using femtosecond laser (IntraLase 60kHz), with a minimum follow-up of 6 months. Pre and post-operative best-corrected visual acuity (BCVA), manifest refraction and topography parameters were collected. Pre-operative corneal wavefront analysis was performed with Pentacam® (OCULUS Optikgerate GmbH). Eyes were divided in two groups: coincident group - preoperative difference between the flattest meridian and coma axis inferior to 30º; no-coincident group - difference equal or superior to 30º.

Results:

Forty-eight eyes were included. At six months, coincident group (n=26 eyes) presented a significant improvement of BCVA (0.42 ± 0.25 pre-operatively to 0.24 ± 0.09 logMAR, p=0.008), spherical equivalent (-4.38 ± 3.14D to -3.25 ± 2.47D, p=0.003) and manifest cylinder (3.68 ± 1.28D to 2.53 ± 1.67D, p=0.020). Topographic parameters also presented a significant decrease (p≤0.028). Regarding no-coincident group (n=22 eyes), BCVA significantly improved (0.39 ± 0.21 to 0.24 ± 0.18 logMAR, p=0.013) with a slight improvement of spherical equivalent (-3.66 ± 4.04D to -3.42 ± 3.01D p=0.047). No significant improvement of refractive cylinder and keratometric parameters was found.

Conclusions:

Eyes with coincident coma and flattest topographic axis presented good results in all the evaluated parameters. No coincident eyes presented good BCVA results, but no significant topographic and refractive improvement, highlighting the need for better implantation guidelines. FINANCIAL INTEREST: NONE