In the AS-SS-OCT assessment, the entire circumference of the angle could be analyzed for 19 eyes in the dark and 14 eyes in the light, whereas 24 eyes in the dark and 29 eyes in the light had the range of angles that could not be analyzed. The UR averaged 35.4 ± 41.2°, 9.8 ± 13.1°, 18.3 ± 31.9°, and 12.3 ± 15.7° in the superior, temporal, inferior, and nasal quadrants in the dark, and 37.2 ± 38.4°, 10.4 ± 15.1°, 24.6 ± 35.8°, and 12.3 ± 16.7° in the light, respectively. To estimate the influence of the UR on whether the entire ITC range was detected, the ITC range was compared between the UR-negative and UR-positive eyes. There was no significant difference in age, refraction, central AC depth, or Shaffer grade in the superior, temporal, inferior, or nasal quadrants between the UR-negative and UR-positive eyes (
P = 0.07, 0.06, and 0.14, Mann–Whitney test, and 0.31, 0.57, 0.60, and 0.43, χ
2 test in the dark,
P = 0.44, 0.98, and 0.53, Mann–Whitney test, and 0.14, 0.46, 0.14, and 0.34, χ
2 test in the light, respectively). There was also no significant difference in the ITC range between the UR-negative and UR-positive eyes in dark and light conditions (
P = 0.33 in the dark,
P = 0.25 in the light, Mann–Whitney test), suggesting that the presence of the UR in our subject eyes had no substantial effect on the ITC range averaged in the subject eyes (
Table 4).