Chamber depth, iris curvature may significantly affect risk of acute primary angle closure

November 15, 2013

Shallower anterior chamber depth (ACD) and a smaller iris curvature (I-Curv) are the two primary anterior segment biometric parameters associated with acute primary angle closure during an attack, according to a recent study published in Ophthalmology.

Shallower anterior chamber depth (ACD) and a smaller iris curvature (I-Curv) are the two primary anterior segment biometric parameters associated with acute primary angle closure during an attack, according to a recent study published in Ophthalmology.

For this prospective, comparative case series, 31 consecutive patients with acute primary angle closure were included. Mean patient age was 60 years, mean IOP was 3.8 mmHg in the eye with acute primary angle closure and 4.2 mmHg in the fellow eye before treatment (P

All patients underwent AS-OCT imaging of both eyes before therapeutic interventions were undertaken. Custom software was used to measure ACD, anterior chamber area (ACA), anterior chamber volume (ACV), I-Curv, iris area (I-Area), lens vault (LV), angle opening distance (AOD750), trabecular iris space area (TISA750), and iris thickness at 750 μm from the scleral spur (IT750).

After adjusting for pupil diameter, researchers found that APAC eyes had smaller ACD, ACA, ACV, I-Curv (all P

An optimal model that was comprised of pupil diameter, ACD, and I-Curv explained 36.7% of the variance in the occurrence of acute primary angle closure, with ACD accounting for 18.1%, and I-Curv for 14.1% of this variance.

"These findings present new insights into the anterior segment biometric parameters of acute primary angle closure and fellow eyes before therapeutic interventions," noted C.A. Chelvin, MBBChir, FRCS(Ed) and fellow researchers from the Singapore Eye Research Institute and Singapore National Eye Center, Singapore. "Anatomic changes in the anterior segment explained only about one-third of the variance in acute primary angle closure occurrence, and the role of nonanatomic factors require further investigation," they concluded.

For study results, click here.