The adaptive effect of narrowing the interocular separation on the AC/A ratio.
The purpose of this study was to determine whether the response AC/A ratio could be altered when the subject's interpupillary distance (IPD) was optically halved. We measured the changes in the AC/A ratio for 10 subjects after using the optical device for 30 min. Accommodative response was measured using a Canon R-1 optometer, and vergence response was measured with an ASL 210 Eye Movement Monitor. The average AC/A ratios were 1.20+/-0.35 (SD) (MA/D) and 0.84+/-0.39 (MA/D) before and after wearing the device, respectively. The decrease in AC/A ratio was statistically significant (p=0.01). This was mainly caused by a reduction in the slope of the accommodative vergence. The results of this study suggest that the AC/A ratio can be decreased if an IPD-narrowing device is used. A possible application of this mechanism in the study of myopia is discussed.
Jiang
Bai-Chuan
BC
College of Optometry, Nova Southeastern University, 3200 S. University Dr., Ft. Lauderdale, FL 33328, USA. bjiang@nova.edu
Ramamirtham
Ramkumar
R
D000065:Accommodation, Ocular / Q000502:physiology*; D000221:Adaptation, Ocular / Q000502:physiology*; D000328:Adult; D003290:Convergence, Ocular / Q000502:physiology*; D005145:Face / Q000033:anatomy & histology*; D006801:Humans; D011680:Pupil; D011930:Reaction Time; D014787:Vision Tests