Changes of Dynamic Stereoacuity Depending on Distance between Rods and Rod Thickness in Three Rods Test

Abstract

Purpose: To determine whether the distance between objects and the size of object are factors to be able to affect dynamic stereoacuity. Methods: Subjects were 37 adults (26 males and 11 females) with an average age of 23.89±1.76. Refractive error was fully corrected for all subjects and each visual acuity of them was over 0.9. Three rods test was performed for measurement of stereoacuity. The viewing angles from left rod to right rod were set 5°, 10°, and 15° and the rod thickness used 7 mm, 14 mm, and 21 mm, respectively. Stereoacuity was repeatedly measured three times in each test condition at 2.5 m distance, and reported the average value of them. Results: When rod thickness was 7 mm or 14 mm, dynamic stereoacuity decreased as the viewing angle increased, and they were significantly decreased (p<0.01) at viewing angles of 10° and 15° as compared with that of at 5°, respectively. When rod thickness was 21 mm, dynamic stereoacuity decreased as the viewing angle increased, especially, that of at 15°decreased significantly (p<0.01) as compared with that of at 5°. The dynamic stereoacuity depending on the rod thickness have an increasing tendency as the rod thickness increased. Conclusions: The viewing angle between objects and the size of viewing object were factors that affect to dynamic stereoacuity.