Rapid ganglion cell complex thinning associated with faster central visual field decline
Rapid ganglion cell complex deterioration correlated with faster rates of central visual field decline, highlighting the importance of macular imaging for monitoring at the time of glaucoma diagnosis, researchers reported.
“These findings support use of longitudinal macular OCT scans assisting clinical decision-making for glaucoma and also may guide possible intensification of therapy in high-risk patients,” Golnoush Mahmoudinezhad, MD, MPH, an ophthalmology research fellow at the Shiley Eye Institute at University of California, San Diego, and colleagues wrote in JAMA Ophthalmology.
In a retrospective cohort study, Mahmoudinezhad and colleagues examined whether the rate of ganglion cell complex (GCC) thinning is associated with the rate of central visual field loss in 202 eyes of 139 adults (mean age, 68.7 years; 48.2% women; 31.7% African American; 9.4% Asian; 57.6% white) with primary open-angle glaucoma and suspected glaucoma enrolled in the Diagnostic Innovations in Glaucoma Study and the African Descent and Glaucoma Evaluation Study. Researchers monitored participants from June 2014 to January 2019 (mean initial follow-up period, 1.8 years).
The rates of GCC thinning were measured using three OCT scans. Central visual field (10-2) mean deviation during the follow-up period was utilized to measure the rates of central visual field loss.
Researchers reported that during the initial follow-up period, GCC change was –0.56 µm/year. In addition, 80.7% of eyes were slow OCT progressors with a –0.3 µm/year rate of GCC thinning, while 19.3% were fast OCT progressors with a –1.6 µm/year rate of GCC thinning, accounting for a difference of –1.3 µm/year (P < .001).
Further, the rate of 10-2 visual field mean deviation worsening was –0.1 dB/year for slow OCT progressors and –0.34 dB/year for fast OCT progressors (difference, –0.26 dB/year; P = .008).
“This finding may be clinically relevant, especially for early detection of patients with glaucoma who are at high risk of central [visual field] loss and for whom additional ocular hypotensive treatment should be considered,” Mahmoudinezhad and colleagues wrote.
Perspective
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Choosing which testing to order in glaucoma patients not only requires expert knowledge but also affects outcomes. This study gives us further incentive to employ macular scans and obtain critical data in glaucoma management.
While retinal ganglion cells are among the last surviving cells in advanced disease, their early rapid decline may foreshadow the hastening of central visual field defects. The 24-2 visual field test has significant gaps in the central degrees of field. Many patients would benefit early on from a 10-2 in concert with GCC scans. Clearly, doing both types of visual fields on one day or bringing patients back to complete the other test has its own drawbacks. A hybrid test like the 24-2C, which combines a conventional 24-2 with selected central points of a 10-2 (that are most likely to be affected by glaucoma) is an alternative. This option is convenient, but when central losses are detected, a full 10-2 is in order. While most OCTs now have the ability to analyze the GCC, we must not forget to get that extra piece of information early in our glaucoma workup. In patients at high risk for central visual field loss this can be critical in improving their long-term outcome and quality of life.
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