Disc-fovea angle measurements for objective cyclotorsion review
Reviewed by Fiona Rowe

The author measured the disc-fovea angle (DFA) in 249 healthy people (81 male, 168 female) as part of a retrospective study of 44 to 70-year-old adults. These were grouped as (1) aged 44 / 45 years, (2) aged 59-70 years, and (3) >74 years. These groups allowed the effect of aging to be evaluated. Angle was measured with digital fundus photographs using the Kowa VX-10 fundus camera. Group 1 included 58 patients (44.4 ±0.5 years), group 2, 129 patients (63.7 ±3.6 years) and group 3, 62 patients (81 ±3.8 years). Total DFA was the sum of right and left eye DFAs. There was a low correlation for age and total DFA. A significant difference was found for left eye DFA across all age groups and DFA of the left eye was larger for group 3 vs group 1. There was no significant difference for the right eye. The total and right eye DFA was larger for females than males. Overall, the results show the angle of objective cyclotorsion increases with age and is different between males and females, and right and left eyes. Two reasons are postulated for the increase with age: (1) age-related sagging of lateral rectus muscles and (2) reduction in phoria adaptation with age. The author acknowledges limitations, including use of fundus photographs as a measurement allows systematic errors due to slight movements of head and eye position when taking images; lack of calculated sample size; limited to the Japanese population.

Objective excyclotorsion increases with aging in adults.
Oohira A.
STRABISMUS
2022;30(3):183-9.