Patterns of glaucoma progression in retinal nerve fiber and macular ganglion cell-inner plexiform layer in spectral-domain optical coherence tomography

Purpose To evaluate the progressive changes of circumpapillary retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GCIPL) thicknesses measured by spectral-domain optical coherence tomography (Cirrus SD-OCT) in open-angle glaucoma. Methods One hundred-fourteen eyes of open-angle glaucoma patients with localized RNFL defect who had 3 years’ worth of annual RNFL photography and OCT measurements were enrolled in this retrospective study. The progression rates of serial RNFL and GCIPL thicknesses (µm), angular width (°) and area (mm 2 ) of defect on RNFL and GCIPL deviation maps were determined by linear mixed-effect models. Results Over a mean follow-up period of 3.16 years, 50 patients out of a total of 114 patients were classified as progressors based on the structural evaluation. The progressors showed significantly higher progression rates in average, 6 and 11 o’clock sector RNFL thicknesses, angular width and area of defect in RNFL deviation map, as well as inferotemporal and minimum GCIPL thicknesses than the non-progressors. The thicknesses of the 6 o’clock sector RNFL and minimum GCIPL exhibited the highest reduction rates among the RNFL and GCIPL parameters assessed, respectively. Conclusions When evaluating glaucoma progression by OCT, careful observation of the average, 6 and 11 o’clock sectors in RNFL and inferotemporal and minimum GCIPL thicknesses can be helpful. We can effectively assess early changes of glaucoma progression with GCIPL thickness as well as RNFL thickness.