Clinical Measurement of the Angle of Ocular Movements in the Nine Cardinal Positions of Gaze

Abstract

Purpose: To measure the maximum angle of ocular versions using photographs of the 9 cardinal positions and a modified limbus test. Design: An evaluation of diagnostic technology; a prospective observational study. Participants: We enrolled 104 healthy subjects, 20 to 40 years of age. Methods: Photographs were obtained in the 9 cardinal positions of gaze and the images were processed using Photoshop. The images were analyzed using the Image J program to measure the angle of version. The maximum angle of the 9 cardinal positions was quantified using a modified limbus test. Main Outcome Measures: We measured the maximum angle of ocular versions in the 9 cardinal positions of gaze. We also compared the results for males and females. Results: The mean angles of maximum version were adduction 47.4 degrees, abduction 46.4 degrees, elevation 31.8 degrees, depression 47.8 degrees, elevation in adduction 39.7 degrees, elevation in abduction 40.7 degrees, depression in adduction 52.7 degrees, and depression in abduction 49.2 degrees. The mean angle of maximum elevation was significantly smaller than that of depression (P< 0.001). There were no correlations between the angle of maximum version and age, spherical equivalents, or axial length. The angle of maximum version for males was significantly greater than that for females, except for inferior gaze. Conclusions: A modified limbus test using photographs of the 9 cardinal positions is an objective and reproducible tool for quantifying ocular movement. Considering its simplicity, ease of use, and low cost, it has clear applications in clinical practice.