Understanding Patterns of Preserved Retinal Ganglion Cell Layer in Advanced Glaucoma as Seen With Optical Coherence Tomography

Precis: Using optical coherence tomography (OCT), eyes with advanced glaucoma were found to have a wide range of patterns of damage that were consistent with the natural history of progression based on a model of macular progression. Purpose: To understand the patterns of preserved retinal ganglion cells in eyes with advanced glaucoma using OCT and a model of progression of the central macula. Methods: OCT GCL thickness was measured in 94 eyes with advanced glaucoma, defined as glaucomatous eyes with a 24-2 MD (mean deviation) worse than -12 dB. A commercial report supplied the GCL thickness in 6 sectors of the thick, donut-shaped GCL region around the fovea. For each eye, the 6 sectors were coded as green (within normal limits, WNL), yellow (<= 5th, >= 1st percentile), or red (<1st percentile). Results: In all 94 eyes, one or more of the 6 sectors of the donut were abnormal (red or yellow), while all 6 sectors were red in 52 (55%) of the eyes. On the other hand, 33 eyes had one or more sectors WNL (green). While the pattern of donut damage varied widely across these 33 eyes, 61 of the 66 hemiretinas were consistent with a temporal-to-nasal progression of damage within each hemiretina as predicted by our model. Conclusions: All eyes with advanced glaucoma had damage to the critically important central, donut-shaped GCL region. This region showed a wide range of patterns of damage, but these patterns were consistent with the natural history of progression based on a model of macular progression. These results have implications for the clinical identification of macular progression, as well as for inclusion criteria for clinical trials seeking to preserve central macular function.