John Lovasik O.D.


Changes in fundus coloration may be pathognomonic of imminent or subclinical ocular disease; increasing pallor of the neuroretinal rim and subtle changes in the coloration of the macula may signal glaucomatous damage of the optic nerve head (ONH) and diabetic maculopathy respectively. Clinically, suspect eyes are typically followed by serial photography. However, even when such photodocumentation is available, subtle changes may escape detection unless chromatic attributes of the fundus can be quantified reliably. At the present time ophthalmic digital imaging systems are principally aimed at measuring and displaying changes in the ONH topography in glaucoma in the black-white or pseudo-color mode. Existing photographic procedures to compare any changes in the coloration of two fundus pictures are primarily qualitative in nature or based on simple visual inspection both of which are flawed by their subjectivity and lack of point by point analysis of fundus details. In the present study we describe the utility of an image analysis system originally designed for histological applications, in ophthalmic imaging. We demonstrate its high sensitivity to detect slight changes in local color by showing quantifiable differences in the chromatic attributes of the ONH during normal cardiac pulsation. Ten fundus photos were taken randomly and ten others when subjects were electronically coupled with the fundus camera via a customized finger pulse detector such that a slide could only be taken within a narrow predetermined interval after systole. Slides were then digitized and analyzed in true color via a high resolution Sony DXC-750 three CCD camera mated with the Nikon MicroAnalyst system which applied criteria of hue, saturation and brightness to each region of interest. The coloration of the ONH for these two test conditions differed significantly (pFOCAL LOSS OF EPITHELIUM ASSOCIATED WITH HYDROGEL CONTACT LENS WEAR


Year: 1992

Program Number: Poster 27

Author Affiliation: n/a

Co-Authors: Marc O.D.

Co-Author Affiliation: n/a

Room: Great Hall