Primary angle-closure glaucoma (PACG) is often described as a bilateral disease with an asymmetrical presentation. In clinic, this is a familiar scenario: one eye arrives in crisis with acute primary angle closure (APAC), while the fellow eye appears relatively stable, with normal intraocular pressure (IOP) and no optic nerve damage. But how “normal” is that contralateral eye – and are there measurable anatomical clues that might help us stratify risk earlier?
A new study from Nanchang University, China, takes a closer look at the fellow eyes of PACG patients, comparing anterior segment biometric features between fellow eyes of APAC patients (F-APAC), fellow eyes of chronic PACG patients (F-CPACG), and healthy controls, using ultrasound biomicroscopy (UBM).
The investigators enrolled 94 eyes from 94 participants: 42 F-APAC, 30 F-CPACG, and 22 healthy controls. Importantly, the fellow eyes included had IOP <21 mmHg, no glaucomatous optic neuropathy, and no visual field defects – essentially, eyes that could be dismissed as “unaffected” in routine practice.
Using panoramic UBM imaging, the team quantified key anterior segment parameters, including anterior chamber depth (ACD), angle opening distance (AOD500), trabecular iris space area (TISA500), trabecular iris angle (TIA500), iris curvature (IC), and lens vault (LV).
Both fellow-eye groups showed a significantly more crowded anterior segment than healthy controls. Compared with healthy eyes, F-APAC eyes had smaller ACD, anterior chamber width, anterior chamber area, and narrower angle metrics, alongside higher LV, relative position lens vault (RPLV), and greater iris curvature. Similarly, F-CPACG eyes also demonstrated reduced ACD and angle parameters compared with healthy controls, with higher LV, RPLV, peripheral iris thickness maximum (PITMAX), and iris curvature.
For glaucoma specialists, the message is clear: the fellow eye in unilateral PACG is anatomically high-risk, even before optic nerve damage is detectable. While the study is limited by sample size and its cross-sectional design, it reinforces the need for careful fellow-eye assessment – and suggests that lens vault, in particular, may help distinguish acute from chronic angle-closure predisposition.
A new study from Nanchang University, China, takes a closer look at the fellow eyes of PACG patients, comparing anterior segment biometric features between fellow eyes of APAC patients (F-APAC), fellow eyes of chronic PACG patients (F-CPACG), and healthy controls, using ultrasound biomicroscopy (UBM).
The investigators enrolled 94 eyes from 94 participants: 42 F-APAC, 30 F-CPACG, and 22 healthy controls. Importantly, the fellow eyes included had IOP <21 mmHg, no glaucomatous optic neuropathy, and no visual field defects – essentially, eyes that could be dismissed as “unaffected” in routine practice.
Using panoramic UBM imaging, the team quantified key anterior segment parameters, including anterior chamber depth (ACD), angle opening distance (AOD500), trabecular iris space area (TISA500), trabecular iris angle (TIA500), iris curvature (IC), and lens vault (LV).
Both fellow-eye groups showed a significantly more crowded anterior segment than healthy controls. Compared with healthy eyes, F-APAC eyes had smaller ACD, anterior chamber width, anterior chamber area, and narrower angle metrics, alongside higher LV, relative position lens vault (RPLV), and greater iris curvature. Similarly, F-CPACG eyes also demonstrated reduced ACD and angle parameters compared with healthy controls, with higher LV, RPLV, peripheral iris thickness maximum (PITMAX), and iris curvature.
For glaucoma specialists, the message is clear: the fellow eye in unilateral PACG is anatomically high-risk, even before optic nerve damage is detectable. While the study is limited by sample size and its cross-sectional design, it reinforces the need for careful fellow-eye assessment – and suggests that lens vault, in particular, may help distinguish acute from chronic angle-closure predisposition.
