New digital methods: remodelling the harms tangent scale setting.

PURPOSE: The aim of this study is to present a feasibility study to evaluate and compare a self-constructed, digital-based tangent scale using the Harms tangent screen test for the examination of patients' strabismus angles.

METHODS: The documented strabismus angles of 10 patients were measured at nine gaze-positions and compared using the Harms tangent screen test (Harms Screen) and a self-constructed digital screen test (Digital Screen). The primary outcome is the difference in the measured angles between both methods. Secondary outcomes include the duration of the examinations and the diagnostic conclusion based on the results of the measurements.

RESULTS: The datasets from 10 of 13 patients were used for comparisons (median age 52 years; females 5; males 5). All measurements showed a mean of 1.77° (SD 2.95°) in horizontal deviations and 1.11° (SD 2.23°) in vertical deviations. The two methods showed differences (> 5°) in 12 cases (13.3%) for horizontal angle measurements and in four cases (4.4%) for vertical angle measurements. The median examination time was 238 s (range 60-430 s) for the Harms Screen and 150 s (range 120-600 s) for the Digital Screen tests. The diagnostic conclusions were identical for both methods.

CONCLUSIONS: The feasibility of the experimental digital setup in principle is shown. Despite some deviations in the measured strabismus angles, the resulting diagnosis of the paresis was identical. The new method showed a reduction of examination time.