Objective excyclotorsion increases with aging in adults.

Introduction: It has been reported that the disc-fovea angle (DFA), a measure of objective cyclotorsion, increases with age. DFA was measured in three age groups of adults and the effects of age, sex, and laterality on DFA is reported.

Methods and subjects: A retrospective study was performed on patients who had a glaucoma checkup or who visited for suspected cataract, who underwent fundus photography between 2013 and 2021. Patients with visual acuity <0.7, axial length >27 mm, strabismus or ocular diseases affecting fusion were excluded. DFA was measured from digital fundus photographs obtained from 249 participants comprising three age groups (group I, 44.4 ± 0.5 years, n = 58; group II, 63.7 ± 3.6 years, n = 129; group III, 81.0 ± 3.8 years, n = 62). The sum of right- and left-eye DFAs is named as total DFA.

Results: Dunnett's post-hoc test after ANOVA showed that the left-eye DFA and total DFA of group III were significantly larger than those of group I (p = .01 and p < .01, respectively). Total DFA of female participant (15.6 ± 4.7°, n = 168) was significantly larger than that of male participant (13.9 ± 4.3°, n = 81) (p < .01). The DFA of the left eye (8.2 ± 3.5°, n = 249) was significantly larger than that of the right eye (6.8 ± 3.3°, n = 249) (p < .001). Group III was subdivided based on eye dominance (right eye dominance, n = 36; left eye dominance, n = 13; NA, n = 13). The DFA in the nondominant eye (9.7 ± 4.6°) was significantly larger than that in the dominant eye (7.4 ± 3.7°) (p < .01).

Discussion: This study found a slight increase of DFA with age. Furthermore, DFA in female or DFA in the left-eye was larger than DFA in male or in the right-eye.