Proposal of Tear Meniscus Measurement for Minor Dry-eye Detection Using Smart-phone Camera and Ring-light

A meniscus height measurement method for dry-eye detection using a low-priced small portable LED ring-light and a smart phone was discussed. The ring-light was clearly reflected in the cornea and the lower part of the eye called tear meniscus, where tears were collected. The diameter of the circle reflected in the cornea and the length from the top to the bottom of the distorted circle reflected in the meniscus were measured through manual pointing operation. The length was normalized by the diameter to be the measured; the meniscus height was not affected by the distance from the camera to the eye. If the meniscus height is low, it indicates a dry -eye. Our experiments demonstrate that our method is as effective as a system using medical equipment.