Chinese persons in this cohort had relatively low baseline iris area, but less loss of iris area on pupil dilation than other groups, a feature also associated with greater prevalence of past acute AC attack. Disproportionate peripheral redistribution of iris area on dilation may contribute to AC.

The CM method was the most successful and least variable method of SS marking, which was more difficult in narrow angle and brown eyes. Variability of SS placement had a large effect on angle parameters and iris concavity ratio.