In his talk “Short-Term Detection of Fast Progressors in Glaucoma: The FAST-PACE (Progression Assessment Through Clustered Evaluation) Study” at the 2024 American Glaucoma Society annual meeting, Dr. Felipe Medeiros discussed how intensive clustered glaucoma testing could have the potential “to detect a substantial proportion of eyes experiencing rapid glaucoma progression within a short time interval.”
“By the time glaucoma is detected, there is already significant visual field loss,” he began, with blindness a relatively common occurrence largely influenced by the severity of the disease at diagnosis and the rate of progression. A study1 published in 2017 looked at more than 1,000 eyes over 2–5 years and found that more frequent testing shortened the window of time necessary to diagnose progression. Whereas it took ~5 years to diagnose progression with annual testing, testing 3 times a year shortened the window to ~2.6 years, and daily testing identified progression in ~11 months.
The Fast-PACE prospective, observational cohort study2 sought to determine if intensive clustering of functional and structural testing could identify eyes with rapid progression of primary open-angle glaucoma (POAG) within a short time period. In this study, 125 eyes of 65 patients with POAG underwent 24-2 and 10-2 standard automated perimetry (SAP) testing and spectral domain OCT (SD-OCT) scans in 2 5-visit clusters 6 months apart, followed up by single visits every 6 months until the end of the 2-year follow-up period. Progression was assessed using trend analyses of SAP mean deviation (MD) and retinal nerve fiber layer (RNFL) thickness.
Diagnostic Accuracy
A total of 30 eyes of the 125 eyes (24%) were progressing by function, structure, or both within the 6-month cluster testing period. A total of 19 eyes (15%) progressed over the 6-month clustering period based on SAP 24-2 MD. Only 1 eye out of 19 (15% of total 125 eyes) with fast progression during the overall 2-year follow-up was not detected as a fast progressor during the 6-month cluster testing period, for a sensitivity of 93% for fast progression. Fourteen eyes progressed on SAP-10-2 MD. Sixteen eyes progressed by global RNFL thickness; 50% progressed by visual fields with high specificity. Of the 90 eyes that did not progress during the overall follow-up period of 2 years, 85 also did not progress during the 6-month period, for a specificity of 94% (CI 88–98%). Based on these findings, Dr. Medeiros suggests that it is possible for clustered testing to identify glaucomatous changes in only 6 months, and statistically significant ones.
Conclusions
“We need to focus our efforts on the fast progressors and detect them much earlier,” recommended Dr. Medeiros. He cited a promising example from this study of the potential benefits, describing a patient with severe glaucoma at baseline who progressed during the 6-month clustering period and then received a trabeculectomy that stopped the progression and stabilized IOP measurements for the remainder of the 2-year follow-up period. With further testing and validation, Dr. Medeiros believes that cluster testing could have value in defining earlier endpoints for clinical trials, providing earlier detection and intervention to minimize irreversible vision loss, and allowing for better assessment of high-risk patients.
Dr. Medeiros acknowledged that clustering tests might be difficult to implement as a strategy in a clinical setting. However, the number of tests conducted within a 6-month period had a major effect: for example, 4 tests identified about 75% of fast progressors, and 3 tests identified about 50% of fast progressors. Dr. Medeiros suggests that new technologies and perimetric techniques could make it easier to perform the tests.
References
1 Wu Z et al. Ophthalmology. 2017;124(6):786-792.
2 Medeiros F et al. Ophthalmology. 2024. [online December 2023]