Association Between Rate of Ganglion Cell Complex Thinning and Rate of Central Visual Field Loss

Abstract

Whether rapid ganglion cell complex (GCC) thinning during an initial follow-up period is associated with rates of central visual field loss over time is unclear but important to understand because risk of glaucoma progression can help guide treatment intensity. To investigate the association between the rate of GCC thinning during initial follow-up and the rate of central visual field loss. This retrospective cohort study assessed patients older than 18 years with glaucoma at a tertiary glaucoma center who were followed up from June 18, 2014, to January 11, 2019. Data analysis for the current study was undertaken in March 2022. Initial rates of GCC thinning were obtained from global GCC thickness values of the first 3 optical coherence tomography (OCT) scans. Rates of central visual field loss were assessed as the change in central (10-2) visual field mean deviation during the 4.7-year follow-up period by univariable and multivariable linear mixed-effects models. Eyes were categorized as slow (>-1 μm/y) or fast (≤-1 μm/y) progressors based on rates of GCC thinning. The cohort consisted of 202 eyes of 139 patients (mean [SD] age, 68.7 [10.0] years; 72 male [51.8%]); 44 African American patients (31.7%), 13 Asian patients (9.4%), 80 White patients (57.6%), and 2 patients who identified as other race and ethnicity (1.4%) were analyzed. The rate of GCC change was -0.56 μm/y (95% CI, -0.66 to -0.46 μm/y) during a mean initial follow-up of 1.8 years (95% CI, 1.7-2.0 years). A total of 163 eyes (80.7%) were slow OCT progressors, and 39 (19.3%) were fast OCT progressors, with rates of GCC thinning of -0.3 μm/y (95% CI, -0.4 to -0.2 μm/y) and -1.6 μm/y (-1.8 to -1.3 μm/y), respectively. The rates of 10-2 visual field mean deviation worsening among slow and fast OCT progressors were -0.10 dB/y (95% CI, -0.16 to 0.00 dB/y) and -0.34 dB/y (95% CI, -0.51 to -0.16 dB/y), respectively (difference, -0.26 dB/y; 95% CI, -0.45 to -0.07 dB/y; P = .008). In this cohort study, rapid GCC thinning during an initial follow-up period was associated with faster rates of central visual field decline. 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.