A diagnostic approach that clusters multiple tests of visual field and retinal imaging in an intense 6-month period has demonstrated the potential to identify patients likely to have fast-progressing glaucoma, according to a prospective cohort study presented on March 2, 2024, at the annual meeting of the American Glaucoma Society in Huntington Beach, California.
The Fast-PACE study included 125 eyes of 65 patients with primary open-angle glaucoma (POAG) before significant anatomical and visual deterioration occurred, who had two clusters of testing 6 months apart. Each cluster consisted of five separate office visits in which the patients had standard automated perimetry (SAP) 24-2 and 10-2 to evaluate loss of the visual field and optical coherence tomography (OCT) to assess the integrity of the retinal nerve fiber layer (RNFL), a key biomarker of the integrity of the optic nerve head in glaucoma.
‘Remarkable Result’
Results of SAP 24-2 testing showed that 19 eyes (15%) progressed over the 6-month period, whereas SAP 10-2 testing showed that 14 eyes (11%) progressed, Felipe Medeiros, MD, PhD, vice chair for translational research at Bascom Palmer Eye Institute at the University of Miami School of Medicine, reported.
RNFL thickness showed 16 eyes (13%) progressed in the 6-month period, and a total of 30 eyes (24%) demonstrated progression based on SAP or OCT testing or both modalities, he said. The study was published recently in Ophthalmology.
“A clustered testing approach was able to identify fast progression in glaucoma in only 6 months,” Medeiros told Medscape Medical News. “This is a remarkable result as it will lead to much faster trials. Also, application in clinical practice will result in prompt identification of those fast progressing eyes at greatest risk for vision loss.”
Identifying fast progressors in POAG has been a challenge because patients don’t get SAP testing frequently enough, Medeiros told meeting attendees. His group previously reported that detecting even fast progression of POAG with annual SAP testing may take 5 years.
“As you know, clinicians don’t even do annual visual field tests; the average is even less than that. So by the time patients are detected as deteriorating they have lost a significant amount of visual field,” he said.
The study found the median rate of visual field change in progressors was a loss of 2.70 dB per year, whereas nonprogressors gained 0.02 dB a year.
“Current practice involves insufficient testing that leads to delayed detection of glaucoma progression and irreversible loss of vision,” Medeiros told Medscape Medical News.
Analyzing the results of the clustered SAP testing showed changes that would not be evident with a less frequent interval between tests, Medeiros said.
The clustering approach proved highly reliable, he added. During the 2-year follow-up period, 35 eyes progressed, 25 (71%) of which progressed during the 6-month cluster period, demonstrating a sensitivity of 71% at 6 months. Through the follow-up, patients had 17 tests on average. When that analysis was reversed, 30 eyes progressed during the 6-month cluster period, 27 of which (90%) progressed during the 2-year follow-up, for a specificity of 90%.
Medeiros acknowledged the challenge in getting patients to have so many tests. ” Clinics are already very busy, and visual field testing is certainly one of the bottlenecks,” he said. “However, our study establishes a framework that demonstrates what is possible. Newer technologies that may allow more efficient testing in practice can then be tested against such framework.”
The study had an 87% patient retention rate, he noted. “We now know that is possible to detect glaucoma progression in a short period of time.” Medeiros said. “Before this study, no one had demonstrated that this was possible.”
Sasan Moghimi, MD, a glaucoma specialist and professor at Shiley Eye Institute at the University of California, San Diego, called clustering test results “an innovative strategy” for detecting rapid glaucoma progression early.
“Early detection of fast progressors is critical both clinically and in randomized clinical trials,” said Moghimi, who was not involved in the latest study. “However, identifying these patients is complicated by the test-retest variability of commonly available clinical tools, such as visual field and optical coherence tomography.”
The clustering methodology, Moghimi added, ” could be applied in clinical trials investigating interventions to slow glaucoma progression and may be of value for short-term assessment of high-risk subjects.”
Yet clustering may prove difficult to implement in the clinic, according to Qi N. Cui, MD, PhD, a glaucoma specialist and assistant professor of at the Hospital of the University of Pennsylvania in Philadelphia.
“The idea that clustering improves progression detection is not a new one, and logistic hurdles in a clinical setting may impede the practical applications of such a testing strategy,” Cui said. “This study, however, may be notable for providing a road map in how to structure glaucoma clinical trials with improved enrollment of fast progressors and for shortening the duration of follow-up necessary to detect progression.”
The study received support from a National Institutes of Health grant. Medeiros disclosed relationships with Novartis, Allergan/AbbVie, Reichert; Carl Zeiss, Galimedix, Biogen, Johnson & Johnson, Stealth Therapeutics, Stuart Therapeutics, Annexon, and Google. Moghimi and Cui have no relationships to disclose.
Richard Mark Kirkner is a medical journalist based in the Philadelphia area.
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