AC/A measurement differences
Reviewed by Fiona Rowe

The authors sought to investigate differences in stimulus accommodative convergence/accommodation (AC/A) ratio using various techniques and accommodative stimuli. The study included 81 orthoptic students; 15 males and 66 females with a mean age of 21 years ±1. Ocular deviation was measured with varied accommodation of up to 10D in 1D steps. In method 1, the angle was measured at 5m and 1/3m distances. In method 2 the angle was measured on the synoptophore. Median stimulus AC/A ratio with low accommodation was 1prism/D at 5m, 2 prism/D at 1/3m and 2.7 prism/D on the synoptophore showing a significant difference between methods. Measurements with high accommodation were 4, 3.7 and 4.7 prism/D respectively showing a significant difference only for 5m and synoptophore measures. The authors conclude there are differences in AC/A ratio values dependent on calculations and types of measurements. There is potential to reduce some differences by using high accommodative stimuli.

Differences in the stimulus accommodative convergence / accommodative ratio using various techniques and accommodative stimuli.
Satou T, Ito M, Shinomiya Y, et al.
STRABISMUS
2018;26(2):53-61.