Effect of pre-operative corneal profile on the efficacy of intrastromal corneal ring segment implantation

Session Details

Session Title: Cornea Surgical II

Session Date/Time: Tuesday 16/09/2014 | 08:00-10:30

Paper Time: 09:33

Venue: Boulevard B

First Author: : V.Ramani MALAYSIA

Co Author(s): :    Z. Azari              

Abstract Details

Purpose:

To establish corneal topographic and tomographic profile that can respond the most from corneal remodelling by implantation of intrastromal corneal ring segment (ICRS).

Setting:

The Tun Hussein Onn National Eye Hospital, Selangor, Malaysia.

Methods:

This cross-sectional retrospective study included 70 eyes with keratoconus who underwent implantation with the Keraring ICRS (Mediphacos, Bela Horizonte, Brazil). Data was collected preoperatively and at 6-months post-operatively. Change in best corrected visual acuity (BCVA) was used to determine the effectiveness of ICRS implantation. Average simulated keratometry (Sim K average), average central corneal thickness, simulated keratometric astigmatism (Sim K Astig), irregular astigmatism index (IAI), opposite sector index (OSI), and thinnest pachymetry (TP) were analyzed with multiple regression analyses. Corneal topographic and tomographic data were acquired using Galilei Dual Scheimpflug Analyzer (Ziemer Ophthalmic System AG, Port, Switzerland).

Results:

A statistically significant difference between pre-operative and post-operative Kmax and minimum pachymetry was identified (Student’s t-test). A multiple regression analysis showed a Pearson correlation between improvement in BCVA and pre-operative Sim K average; Sim K astig, OSI, IAI, and TP were 0.276 (p=0.070), –0.1254 (p=0.225), 0.616 (p<0.001), 0.551 (p=0.001), and –0.498 (p=0.003), respectively. OSI and TP were, sequentially, identified as the best predictors of ICRS implantation outcomes. Adjusted R Square value was 0.454, indicating only a moderate relationship between the predictors and the outcome. OSI value is an indication of decentration of corneal apex. Influence of pachymetry can be related to Barraquer’s Law of Thickness.

Conclusions:

In this study, implantation of an ICRS was more effective in a thinner cornea with a displaced apex.

Financial Interest:

NONE