Posters

Novel OCT tomography to study remodelling of curvature of Bowman�â�€�™s layer following wavefront optimized photorefractive keratectomy

Poster Details

First Author: H.Matalia INDIA

Co Author(s):    R. Chandapura   R. Shetty   R. Shroff   N. Shilpy   M. Francis   A. Sinha Roy     

Abstract Details

Purpose:

To evaluate changes in curvature of Bowman�â�€�™s layer after wavefront optimized photorefractive keratectomy (PRK) using a novel OCT tomography mapping tool

Setting:

Narayana Nethralaya, Bangalore, India

Methods:

OCT topography of corneal layers was generated to analyse the remodelling of the epithelium and underlying stroma after low myopia PRK. Myopic PRK was performed in 15 patients. One eye of each patient underwent manual scraping of epithelium while the other was treated with Epi clear. Epi clear allowed a gentler removal of the epithelium compared to manual scraping. Scheimpflug imaging (Pentacam, OCULUS Optikgerate Gmbh, Germany) and OCT (RTVue, Optovue Inc., USA) scan of the cornea was performed before and after PRK (3 months). The OCT scanner acquired 8 radial 2-D scans of the cornea.

Results:

MRSE was -2.22�Â�±0.19D and -2.77�Â�±0.49D in manual scrapping, Epi clear group respectively. Topographic changes on the anterior corneal surface between Scheimpflug and OCT imaging were similar, e.g., mean-K decreased by 2.190.25D and 2.20.21D respectively. Sub-epithelial curvature(epithelium-stroma interface) after PRK was similar to the anterior corneal surface(air-epithelium interface), when measured with OCT, e.g., mean-K of the sub-epithelial surface decreased by 2.170.2D. Scheimpflug imaging reported increased spherical aberration than OCT after PRK, e.g., spherical aberration increased by -0.230.05m and -0.120.06m when measured on Scheimpflug imaging and OCT respectively. There was no difference in outcomes between manual scrapping and Epi clear.

Conclusions:

This is the first study to quantify the curvatures of the stromal layers with OCT after PRK. New insights were gained, which could be useful for refinement of surgical ablation algorithms. The Scheimpflug imaging may have shown an exaggerated increase in spherical aberration compared to OCT due to its inferior axial resolution.

Financial Disclosure:

NONE