Longitudinal Macular Structure-Function Relationships in Glaucoma

Abstract Purpose To investigate the relationship between longitudinal changes in macular thickness measurements from optical coherence tomography (OCT) and changes in central visual field (VF) in glaucoma patients with central or advanced damage at baseline. Design Longitudinal cohort study. Subjects 116 eyes with ≥3 years of follow-up and ≥5 macular OCT images and central 10° VF tests were selected. Methods OCT superpixels and VF locations were matched correcting for retinal ganglion cell displacement. Superpixel thickness and visual field (VF) total deviation (TD) values, in both logarithmic and linear scales, were averaged within 3 eccentricities (3.4°, 5.6°, and 6.8°) and superior and inferior hemiretinas and hemifields. We estimated pointwise TD rates of change and rates of change at superpixels for full macular thickness (FMT), ganglion cell complex (GCC), ganglion cell-inner plexiform layer (GCIPL) and ganglion cell layer (GCL). Correlation of structural and functional (SF) rates of change were investigated with parametric tests. We compared the proportion of worsening and positive slopes for superpixels and VF test locations (negative vs. positive rates of change with p Main Outcomes Measure Magnitude of correlation between structural and functional rates of change and proportion of worsening and positive slopes as a function of follow-up time. Results The median (IQR) follow-up and number of exams were 4.2 (3.7-4.6) years and 8 (7-9), respectively. The highest correlation of change rates was observed at 3.4° and 5.6° eccentricities (r=0.24, 0.41, 0.40, and 0.40 for FMT, GCC, GCIPL and GCL for 3.4° eccentricity and =0.28, 0.32, 0.31 and 0.32 for FMT, GCC, GCIPL and GCL for 5.6° eccentricity, respectively). Although GCC measures demonstrated the highest overall longitudinal SF correlations, the differences were not statistically significant. Significant structural worsening was more frequently detected than functional deterioration at 3- and 5-year timepoints (p Conclusion Correlations between central structural and functional rates of change were weak to fair in this cohort. Structural changes were detected more frequently than functional changes. Measurements of both structure and function are required for optimal detection of central progression.