Intraocular Pressure Therapy May Slow Primary Open-Angle Glaucoma Progression

According to a recent systematic review from the University of North Carolina, IOP-lowering therapy may potentially slow glaucoma progression in patients with primary open-angle glaucoma (POAG).1

Glaucoma is a leading cause of irreversible vision loss, affecting >70 million people globally; of these, roughly 10% of individuals with glaucoma are bilaterally blind. Glaucoma also often remains asymptomatic until it is severe, which may mean the number of individuals affected is substantially higher. Past surveys have indicated that only 10-50% of people with glaucoma are aware that they have it.2

POAG, the most common form of glaucoma, is frequently linked to elevated intraocular pressure (IOP). This leads to distinctive damage to the optic nerve head, subsequently functionally impairing vision. However, pathophysiological mechanisms behind POAG are still unknown, and clinicians have not defined a diagnostic benchmark.1

“Exploring the behavior of glaucoma progression at an individual level, especially in response to initial treatment, may better elucidate underlying mechanisms and potential therapeutic strategies by creating pure or better-differentiated datasets,” wrote Vihar Naik, MD, department of ophthalmology, University of North Carolina, and colleagues. “The present systematic review seeks to better characterize glaucoma progression by evaluating changes in progression velocity at an individual level in response to IOP-lowering therapy.”1

Naik and colleagues collected data from PubMed, Cochrane CENTRAL, and ClinicalTrials.gov from inception to November 2023. Trials were considered eligible if they were randomized clinical trials of adult (≥18 years) patients diagnosed with POAG, normal tension glaucoma, or ocular hypertension considered progressing. The team included trials regardless of IOP-lowering treatment modality, such as laser trabeculoplasty or filtration surgery, and if target IOP reduction was ≥20% from baseline.1

A total of 641 studies were initially selected for review; 271 duplicates were removed, and the remaining 370 were screened until 3 studies remained for full-text review. In the end, only 1 study was utilized for the study, which followed 780 eyes of 432 patients. Of these, 139 eyes (17.8%) of 109 participants (25.2%) reached the POAG endpoint.1

In these participants, rate of mean deviation (MD) change exhibited a significant difference before and after treatment (-.51 +/- .8 versus -.27 +/- .7 dB/year, respectively, P <.01). This subgroup also demonstrated high individual variability in the MD rate of change. Investigators found a correlation between rate of MD change and IOP reduction using both mean and maximum IOP (P <.001).1

Naik and colleagues also noted that a considerable number of patients among the included study exhibited worse rates of progression post-treatment. They attribute this to various clinical situations, such as insufficient IOP reduction, skewed IOP readings due to corneal properties, or concurrent ocular conditions progressing independently of IOP levels. The team notes that these variations indicate the complexity of glaucoma as a disease and the difficulties inherent in gauging the effectiveness of IOP-lowering treatments.1

Additionally, the inclusion of only 1 study in the systematic review severely limits the applicability of these results. The team was unable to perform a synthesis and subsequent analysis.1

Nonetheless, the team still considers the review a success. The study’s goal was to indicate the variations between individual glaucoma cases, which contrasts with the cohort-level data often used by glaucoma research and treatment response analysis.1

“Additionally, we propose that certain patients may present with glaucoma and a glaucoma-like optic neuropathy, warranting more nuanced analysis,” Naik and colleagues wrote. “This review encourages the use of pre- and post-treatment progression velocities, when practical, in future glaucoma treatment investigations.”1

References

1. Naik V, Ohri S, Fernandez E, Mwanza J-C, Fleischman D. Changes in individuals’ glaucoma progression velocity after IOP-lowering therapy: A systematic review. PLOS One. 2025;20(5). doi:10.1371/journal.pone.0324806

2. Weinreb RN, Aung T, Medeiros FA. The pathophysiology and treatment of glaucoma: a review. JAMA. 2014;311(18):1901-1911. doi:10.1001/jama.2014.3192