Visual field (VF) progression is often a key clue for clinicians to decide on the right course of therapy for their glaucoma patients. A new study in JAMA Ophthalmology found one tracker—the glaucoma rate index— was able to detect long-term VF progression earlier than two other methods: pointwise linear regression or guided progression analysis.
The study also found the glaucoma rate index maintained a low rate of false-positive estimates, and agreement among all three tested methods was moderate at best and showed differences, depending on baseline severity.
Researchers from California and Italy looked at the three different measures to detect VF progression in 729 eyes of 567 primary open-angle glaucoma patients.
Patients in the study had six VF tests performed within about three years. A total of 176 subjects (257 eyes) were treated at a tertiary glaucoma center. Additional data was collected from 391 participants (472 eyes) in the Advanced Glaucoma Intervention Study. The data was collected from 1988 to 2004 and analyzed from 2018 to 2019.
The study compared estimates of VF progression using each of the three methods in addition to a subset of patients with likely VF progression and likely VF stability.
Patients were approximately 66 years old, and slightly more than half were female and white. Baseline mean deviation was about -6.7 and patients were followed up at around nine years.
The proportion of eyes labeled as progressing was 27.7% in guided progression analysis, 33.5% in pointwise linear regression and highest at 52.9% in the glaucoma rate index. The pairwise difference for glaucoma rate index vs. pointwise linear regression was 20%, 25% for the glaucoma rate index vs. guided progression analysis and 6% for pointwise linear regression vs. guided progression analysis.
The glaucoma rate index showed the shortest median time to progression at 8.8 years compared with guided progression analysis and pointwise linear regression, which both showed a rate of more than 16 years. These results were similar in the subgroup with likely progression.
For that subgroup, the proportions of progressing eyes were 73.7% for guided progression analysis, 81.4% for pointwise linear regression and 92.9% for the glaucoma rate index. The pairwise difference for the glaucoma rate index vs. pointwise linear regression was 11.5%, 19.2% for the glaucoma rate index vs. guided progression analysis and 7.7% for pointwise linear regression compared to the guided progression analysis.
|Salazar D, Morales E, Rabiolo A, et al. Pointwise methods to measure long-term visual field progression in glaucoma. JAMA Ophthalmol. April 2, 2020. [Epub ahead of print].|