Automated Measurement of Strabismic Deviations Using a Remote Haploscope and an Infrared Television-Based Eye Tracker

Abstract

A large concave mirror used in a specular display arrangement provides a remote mirror haploscope having superimposed visual fields subtending 50° × 50° at a viewing distance of 80 cm. Strabismic deviations are measured in the nine diagnostic positions of gaze using fixation targets generated and displayed under computer control. Eye movement to alternating target presentation is neutralized automatically using an infrared television-based eye tracker (DBA 606). This automated method is more repeatable and four times faster than conventional prism and cover testing. In adults, horizontal and vertical measurements are obtained for nine gaze positions in an average of 1.2 minutes. Unrestrained children are tested by monitoring and optically maintaining proper alignment of the apparatus with the child's eyes in infrared light, and by using a variety of cartoon figures for fixation targets.

• strabismus
• measurement
• deviometer
• mirror
• haploscope
• eye tracker