Ocular Torsion according to Fixation in Fundus Photograph

ABSTRACT

PURPOSE: We examined the torsional change of eyeballs according to fixation using fundus photography. METHODS: We took fundus photographs of both eyes of the following patients group 1, 10 unilateral superior oblique (SO) palsy patients; group 2, 20 exotropia (XT) patients without vertical strabismus or oblique dysfunction; and group 3, 20 normal subjects, from March 2002 to February 2005, using a fundus camera with and without fixation on the internal fixation device. We examined the torsional angle (alpha) between the horizontal line through the optic disc center and the line connecting to optic disc center with fovea using the Scion Image Program, and compared the torsional change according to fixation. RESULTS: The torsional angle (alpha) was 17.92 degrees with fixation and 18.79 degrees without fixation in paretic eyes of group 1 (p=0.46), and 8.78 degrees with fixation and 9.23 degrees without fixation in sound eyes of group 1 (p=0.36). The torsional angle was 6.35 degrees with fixation and 6.86 degrees without fixation in the right eyes of group 2 (p=0.39), and 6.40 degrees with fixation and 6.95 degrees without fixation in the left eyes of group 2 (p=0.28). In group 3, torsional angle was 6.95 degrees with fixation and 7.25 degrees without fixation in the right eyes (p=0.72), and 7.42 degrees with fixation and 7.48 degrees without fixation in the left eyes (p=0.89). Torsional angle with fixation was smaller than without fixation in all groups, but the differences were not statistically significant. CONCLUSIONS: There was no torsional change according to fixation by fundus photography in unilateral SO palsy patients, XT patients without vertical strabismus or oblique dysfunction, and normal subjects.