Why does acute primary angle closure happen? Potential risk factors for acute primary angle closure.

Acute primary angle closure is an ocular emergency and requires immediate management to avoid blindness. Narrow anterior chamber angle, advanced age, female gender, and Asian ethnic background are considered risk factors for acute primary angle closure. The predictive power of these factors is, however, relatively poor, and many questions remain unanswered because acute primary angle closure eventually develops in only a relatively small proportion of anatomically predisposed eyes. We summarize the potential roles of various factors in the pathogenesis of acute primary angle closure.