Moderate PACG May Be Most Vulnerable to Rapid Functional Loss

In a long-term cohort of 477 Chinese patients with primary angle closure glaucoma, moderate disease showed the fastest visual field decline, revealing a U-shaped relationship between baseline severity and progression. Greater intraocular pressure fluctuation consistently predicted faster loss, while earlier glaucoma surgery was linked to slower worsening—supporting stage-specific monitoring, tighter IOP stabilization and timely surgical intervention to preserve vision. Photo: Alison Bozung, OD. Click image to enlarge. Primary angle-closure glaucoma (PACG) accounts for nearly half of all primary glaucoma cases, carrying a 2.5-fold risk of blindness compared to primary open-angle glaucoma (POAG). Global prevalence of PACG is expected to reach 32 million by 2040, with the Asian population most affected, according to projections. Therefore, understanding the rate and determinants of visual field (VF) deterioration across PACG severity levels is imperative for assessing and managing patients on an individual basis. A new study conducted in China investigated the rate and determinants of VF progression in mild, moderate and severe PACG. Their results were recently published in Scientific Reports. Researchers included Chinese patients with PACG who had ≥5 reliable VFs and ≥5 years of follow-up. Disease severity was classified by baseline mean deviation (MD) as mild (≥-6.0dB), moderate (-6.01 to -12.0dB) or severe (<-12.0dB). VF progression was categorized as slow (>-0.25dB/year), intermediate (-0.25 to 1.0dB/year), or fast (≤-1.0dB/year). From a total of 477 patients, 29.4% had mild, 33.8% had moderate, and 36.9% had severe PACG. The mean age at PACG diagnosis was 66.9 and 46.8% of patients were male. The study results were as follows:Moderate PACG progressed fastest (-0.45 ±0.80dB/year), compared with mild (-0.39 ±0.54dB/year) and severe disease (-0.12 ±1.12dB/year), demonstrating a U-shaped relationship between disease severity and progression. Fast progression was most frequent in moderate PACG (18.0%), compared with mild (12.9%) and severe PACG (10.2%). Fast progressors tended to have greater IOP fluctuation and were older at PACG diagnosis.In mild PACG, faster progression was observed in eyes with greater IOP fluctuation and shorter AL. A longer interval to cataract surgery was associated with reduced odds ratio (OR) of slow progression (OR, 0.90) in mild eyes.In moderate PACG, older age, longer AL, and greater IOP variability were associated with faster visual field loss. In moderate PACG eyes, females and poorer presenting visual acuity were associated with slow progression (ORs of 3.12 and 5.54 respectively). In severe PACG, female sex was associated with slow progression (OR, 2.63). Fast progressors with severe PACG were slightly older, had lower presenting IOP and wider angles at diagnosis. “These findings highlight the role of IOP fluctuations even in early disease,” the authors wrote. “The protective effect of shorter AL against fast progression, though counterintuitive, reflects the complex relationship between ocular biometry and PACG.”The observed U-shaped relationship between baseline VF status and subsequent progression mirrors patterns described in POAG, which highlights the vulnerability of moderate PACG to rapid functional deterioration, they continued. “Our findings also show that slow progressors underwent glaucoma surgery earlier, which supports the benefit of timely surgical intervention in stabilizing disease in line with prior studies showing that glaucoma filtration surgery reduces VF progression, compared to medical therapy,” they wrote in their paper. “Together, these results emphasize that surgical decisions in PACG should consider not only IOP levels but also disease stage and non-IOP risk factors. Clinically, these findings highlight that stage-specific monitoring, aggressive IOP stabilization, and timely surgery are essential to preserve visual function.”Limitations noted in the study included the possibility of selection and information bias in retrospective cohort studies, as well as the use of different SITA-standard and SITA-fast strategies. The authors wrote that this may introduce measurement variability and potentially affect the sensitivity for detecting subtle progression. “In addition, our cohort comprised exclusively ethnic Chinese individuals from Singapore, which may limit the generalizability of our findings to other ethnic populations,” they wrote. “Given reported ethnic differences in ocular biometry, disease susceptibility and progression patterns, extrapolation to non-Asian populations should be undertaken with caution.”Nonetheless, large retrospective cohorts with long-term follow-up provide valuable insights into disease progression in real-world clinical settings, they concluded. “These results support stage-specific approaches to risk assessment, the importance of minimizing IOP fluctuations early, and consideration of timely surgical intervention to preserve long-term vision.”Click here for the journal source. Tan SS, Tan ST, Prasad S. et al. Visual field progression in varying severities of treated patients with primary angle closure glaucoma. Sci Rep. April 1, 2026. [Epub ahead of print.] This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.