A Korean study found 60% of patients with primary angle-closure glaucoma (PACG) had normal intraocular pressure (IOP) at their first visit.

The researchers said this suggested that without gonioscopy, clinicians may misdiagnose PACG as normal tension glaucoma and that anterior chamber depth (ACD) measurements would aid diagnosis of PAGC as even PAGC eyes with initially normal IOP have shallow ACD.

Researchers retrospectively reviewed patients with PACG in a referral center, dividing PACG eyes into two groups: those with normal IOP and those with high IOP (>21 mm Hg) at the first visit.

Of 160 Korean PACG patients identified, 160 eyes were included. Sixty percent (97/160) of the patients had normal IOP at their first visit. The PACG patients with initially normal IOP had significantly longer axial length (mean±SD, 22.99±0.76 vs. 22.74±0.61) and deeper "true" anterior chamber depth (ACD) (2.09±0.27 vs 1.82±0.33) than those with initially high IOP (both P<0.05). Multiple logistic regression revealed that deeper "true" ACD (per 0.1 mm; odds ratio, 1.38) and more hyperopic refractive errors (odds ratio, 1.48) were independent predictors of initially normal IOP in PACG eyes (P<0.05). The prevalence of disc hemorrhage was higher in PACG patients with initially normal IOP than in those with initially high IOP (29.9% vs. 14.3%, P=0.029).