Aims 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.