Greater Initial IOP Fluctuation Predicts Long-term Progression in PACG

Severity of disease may influence progression risk through mechanisms of increased retinal ganglion cell vulnerability, higher IOP fluctuations or impaired ocular blood flow. Photo: Alison Bozung, OD. Click image to enlarge.  Chinese researchers were interested in identifying any associated long-term risk factors of visual field (VF) progression in patients with primary angle-closure (PAC) disease, including suspects (PACS) and those who had developed glaucoma (PACG).Individuals with PACD in the study had at least a 10-year follow-up duration; in total, 129 eyes were included. Visual fields were tested every six months using the 24-2 pattern. The researchers reported that 31.0% of subjects as a whole showed evidence of VF progression during the study, with some notable variations based on condition: 18.2% of angle-closure suspects, 17.3% of PAC eyes and 43.9% of PACG eyes. Statistical models indicated that, in PACG eyes, both higher initial intraocular pressure (IOP) fluctuation and steeper initial VF Index (VFI) slope were linked with disease progression. Other factors linked to VF progression were lower baseline mean deviation in PAC and longer axial length in PACG.IOP spikes and fluctuations may disproportionately damage the optic nerve because of anatomical constraints like shallow anterior chamber and crowded angle in primary angle-closure glaucoma, thus making these eyes uniquely vulnerable to IOP variability. As for the lack of association seen with PACS and PAC eyes and IOP fluctuation, the authors of the study explain in their paper that this may be due to a functionally blocked or damaged trabecular meshwork in PACG eyes. What’s more, greater IOP fluctuations may disrupt homeostatic mechanisms, in turn leading to loading and unloading stress which can lead to subsequent tissue damage and VF progression. As the investigators explain, “our findings provide further insight into the significance of monitoring and regulating IOP fluctuation at the early stage of follow-up in preventing long-term glaucoma deterioration.”No association was expected for PAC eyes without glaucoma, since their IOP levels remained in the normal range. For these cases, “this suggests that IOP-lowering intervention may not be the primary intervention strategy to prevent VF progression among PAC and PACS patients,” the authors elaborate.The steeper initial VFI slope, however, did apply as a risk across all PAC disease subtypes, supporting the importance of regular monitoring for these patients, regardless of disease stage—even in the absence of glaucomatous optic neuropathy. They authors suggest that this finding supports that VFI can be used as a predictive factor, specifically with an initial slope of <-1.0 indicating higher risk of VF progression.Overall, the researchers believe these results highlight the importance of clinicians considering PACS and PAC in their assessments, stating that “this approach not only refines treatment strategies but also improves patient management by addressing potential progression risks at an early stage. These findings highlight the importance of tailored management strategies for patients with different disease severity and refraction.” Click here for the journal source. Shen R, Chan PP, Ling A, et al. Risk factors for visual field progression in primary angle closure disease over 10 years: The CUPAL Study. Invest Ophthalmol Vis Sci. 2025;66(9):59. 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.