Objective: To compare the change in iris-trabecular contact (ITC) area using swept-source optical coherence tomography (SS-OCT) in eyes with primary angle closure glaucoma (PACG) and cataract that underwent phacoemulsification (PE) with intraocular lens implantation alone compared with PE with goniosynechialysis (GSL).

Methods: One eye of 22 patients with PACG with peripheral anterior synechiae (PAS) detected by indentation gonioscopy was randomised into two groups (PE alone (n=11) and PE+GSL (n=11)). The anterior chamber angles were evaluated by SS-OCT under dark conditions before and 12 months after surgery using the three-dimensional angle analysis scan protocol that simultaneously obtains 128 cross-sectional radial scans across the anterior chamber at equal intervals (every 1.4°). The ITC area, defined as the area of extent of the circumferential contact of peripheral iris to the angle wall, was computed automatically by SS-OCT after an observer marked the scleral spurs of all 128 scans of each eye.

Results: The majority of the 22 subjects were women (77.3%) and the mean±SD age was 67.3±5.8 years. The ITC area was significantly reduced in the PE+GSL group compared with the PE alone group (10.2 mm2 vs. 4.6 mm2, β=0.54, p=0.03) after adjusting for age, gender, intraocular pressure, extent of PAS and pupil diameter before surgery. Smaller iris volume at baseline was associated with greater ITC area reduction by PE+GSL (β=-0.728, p=0.03).

Conclusions: Eyes that undergo PE+GSL surgery have a greater reduction in circumferential ITC area than eyes that undergo PE alone.