Digital interferometric demodulation of Placido mires applied to corneal topography

TL;DR

This paper introduces a novel digital interferometric technique for demodulating Placido fringe patterns, enhancing corneal topography analysis by effectively filtering noise from eyelashes and iris structures.

Contribution

It presents the first application of digital synchronous interferometry to demodulate corneal Placido images, improving robustness against common noise sources.

Findings

Successfully demodulated corneal topography images

Enhanced noise filtering in Placido pattern analysis

First implementation of this method in corneal topography

Abstract

This paper presents a novel digital interferometric method to demodulate Placido fringe patterns. This is a synchronous method which uses a computer-stored conic-wavefront as demodulating reference. Here we focus on the experimental aspects to phase-demodulate Placido mires applied to corneal topography. This synchronous method is applied to two topographic Placido images and their de-modulated corneal-slope deformation is estimated. This conic-interferometric method is highly robust against typical "noise" signals in Placido topography such as: reflected eyelashes and iris structures. That is because the eyelashes and the iris structures are high frequency "noisy" signals corrupting the reflected Placido mire, so they are filtered-out by this method. Digital synchronous interferometry is here applied for the first time to demodulate corneal topographic concentric-rings images (Patent pending at the USPTO).