Validity and Ease of Use of a Computerized Hess Chart

Purpose: To investigate agreement between computerized and conventional methods for obtaining Hess charts and to compare relative ease of use of both methods.

Methods: Hess charts of 65 patients were obtained by the use of the computerized Assaf Ocular Motility Analyzer (OMA) and the conventional Lees screen method. The Hess charts produced by each method were compared with a previously described scoring system. Patients compared the ease of testing by using a 5-point Likert scale.

Results: For horizontal deviations of the right eye, the OMA provided a significantly larger (P = 0.0001) deviation (301° ± 267°) than the Lees screen (204° ± 306°). The Lees screen gave a significantly larger score for vertical deviations of the left eye (117° ± 158° vs 96° ± 129°; P = 0.003). Vertical deviations of the right eye and horizontal deviations of the left eye did not differ significantly between tests. Patients required the same amount of time to complete both tests, but the OMA was slightly easier to perform than the Lees screen (Likert score, 1.2 ± 0.5 vs 1.3 ± 0.4; P = 0.046).

Conclusions: The scores measured were larger with OMA in the horizontal and smaller in the vertical direction than with the Lees screen in some directions. Although the OMA did not save time, patients found it easier to perform than the Lees screen. The OMA may be considered a useful alternative to the Lees screen.