Posters

Credibility of percentage tissue altered as a screening formula for post-laser-assisted in situ keratomileusis ectasia

Poster Details

First Author: R.Solanki INDIA

Co Author(s):    K. Sathyamurthy   K. Bhatia                 

Abstract Details

Purpose:

– To calculate the percentage tissue altered (PTA) in post-laser assisted in situ keratomileusis (LASIK) eyes and to validate its role as an independent factor to evaluate ectasia in Indian population.

Setting:

M M Joshi Eye Hospital , Hubli India.

Methods:

333 eyes with normal pre-operative corneal topography by combined Placido and Scheimpflug Imaging based topography system (SIRIUS) underwent LASIK between 2011 and 2014 at a tertiary level teaching hospital in south India. Pre-operatively patient’s refraction, flap thickness (FT), ablation depth (AD), residual stromal bed and central corneal thickness (CCT) were recorded. The formula used was – PTA = (FT+AD)/CCT. PTA was grouped into <0.4 (low risk), 0.4-0.45 (moderate risk) and >0.45 (high risk). All patients were called for follow up and underwent a topography to look for ectasia.

Results:

60.1%, 29.1% and 10.8% patients had PTA of <0.4, 0.4-0.45 and >0.45 respectively. However, after a minimum follow up of 2 years, none of the patients had any sign of ectasia.

Conclusions:

Careful selection of patients is mandatory before proceeding for LASIK. The role of PTA >0.4 as an independent risk factor for post-LASIK ectasia is to be evaluated further. Other factors or a modified formula suitable for Indian eyes needs to be investigated.

Financial Disclosure:

None