The purpose of this project was to evaluate different methods of cornea-to-contact lens fluorescein pattern evaluation in keratoconus patients to find the most repeatable and reliable method for different severity levels. This study also evaluated the repeatability and accuracy of pattern evaluations when completed by people with different levels of experience.
Sixty subjects were chosen with different severity levels of keratoconus. A series of rigid gas permeable lenses in different base curves was applied to each of the subjects’ eyes with fluorescein stain. Each set of lenses included the first definite apical clearance lens, two lenses with a flatter base curve, and three lenses with a steeper base curve. The fits were evaluated by clinicians and photographed using digital and 35mm photography. The lens fits were ranked from flat to steep by the clinicians and the photograph readers ranked the images in the same way. The results were input into an Excel spreadsheet and statistical analyses were run using SAS version 9.1 software.
The novice photograph reader’s repeatability was found to only marginally depend on the severity of keratoconus when using 35mm images, but depended on the severity as well as on which eye is being evaluated with digital images. The novice photograph reader’s accuracy did not depend on the severity of disease. Inter-reader agreement and accuracy both depend on the severity of disease. The accuracy between readers did not significantly depend on the type of photography. The accuracy of clinicians depended on the severity of keratoconus. Overall, more agreement was found between photograph readers than between clinicians.