Using a combination of optical coherence tomography (OCT) to determine retinal nerve fiber layer (RNFL) thinning and visual field (VF) testing to detect mean deviation (MD) worsening is more accurate for detecting moderate to rapid glaucoma worsening than using either method alone, according to a study published in Ophthalmology.
Investigators from Johns Hopkins University School of Medicine included 7392 patients (eyes, 12,150; mean age, 67.6 years; 60.71% women) with OCT scans and 10,958 individuals (eyes, 20,583; mean age, 63 years; 57.08% women) with visual field data in the descriptive, simulation study. The cohort included patients with glaucoma or glaucoma suspects who were followed at the Wilmer Eye Institute between 2013 and 2021. Within-eye rates of changes to RNFL thickness and MD were evaluated.
The OCT assessment revealed that the average change in RNFL thickness was -3.08 μm per year. This change was less pronounced among patients who were glaucoma suspects (mean, -1.57 μm/year) or had mild disease (mean, -1.72 μm/year), and more pronounced among patients with moderate (mean, -6.21 μm/year) or severe (mean, -8.49 μm/year) disease, according to the report.
The VF assessment shows an average MD change of -0.23 dB per year. Stratified by disease stage, the average change was lowest among patients with severe disease (mean, -0.15 dB/year), followed by glaucoma suspects (mean, -0.17 dB/year), mild (mean, -0.27 dB/year), and moderate (mean, -0.31 dB/year) disease.
Overall, using either device to detect moderate to glaucoma worsening resulted in accuracy of less than 50% for both devices. OCT demonstrated an accuracy of 47% for detecting moderate glaucoma worsening and 40% for identifying rapid progression. The VF device performed even worse, with an accuracy of 40% and 27% for detecting moderate and rapid worsening, respectively. Using both devices resulted in a higher accuracy for identifying both moderate (68%) and severe (56%) progression.
“Our results show that more OCT scans and/or VFs are needed to accurately diagnose glaucoma worsening than is currently the norm in clinical practice,” according to the study authors. “Accuracy can be greatly increased if both OCT and VFs are used with the clinician relying on at least one of OCT or VF to be accurate.”
Study limitations include the use of only 1 OCT and VF device and a short study duration.
Bradley C, Herbert P, Hou K, Unberath M, Ramulu P, Yohannan J. Comparing the accuracy of peripapillary OCT scans and visual fields to detect glaucoma worsening. Ophthalmol. Published online February 5, 2023. doi:10.1016/j.ophtha.2023.01.021