Measurement of ocular torsion using digital fundus image.

Computer-based objective measurement of the ocular cyclotorsion using digital fundus photograph was developed. Color digital fundus photographs acquired with the field angle of 60 degrees , 1520 x 1080 in resolution were analyzed. Optic disc and macula were segmented by the program developed on MATLAB, which executed the serial analysis of the Otsu threshold, labeling, Canny edge. The angle between the horizontal line that bisects the optic disc and the line connecting the center of optic disc and macula was measured and compared with the torsion determined by the specialist. Optic disc and macula were segmented and the mean of the calculated angle was 3.02+/-1.24 degrees . The mean of the torsion determined by the specialist was 3.13+/-1.98 degrees and there was no difference between the two. The measurement of the cyclotorsion using computer program showed good coincidence with that of the specialist and it can be a good candidate as a tool helping precise diagnosis and the objective evaluation of the disease for the physicians.