Macular Ganglion Cell–Inner Plexiform Layer Loss Precedes Peripapillary Retinal Nerve Fiber Layer Loss in Glaucoma with Lower Intraocular Pressure

Abstract Purpose To investigate which clinical measures influence whether an individual demonstrates earliest glaucomatous structural progression on peripapillary retinal nerve fibre layer (pRNFL) or macular ganglion cell-inner plexiform layer (mGCIPL). Design Prospective longitudinal cohort study. Participants 271 eyes from 207 individuals with statistically significant evidence of glaucomatous progression on optical coherence tomography (OCT)-Guided Progression Analysis (GPA) software were drawn from a total of 1271 eyes from 686 individuals categorized as glaucoma suspect or having early manifest glaucoma undergoing glaucoma surveillance. Methods Individuals demonstrating earliest evidence of longitudinal progression on mGCIPL GPA event analysis were compared to individuals demonstrating evidence of earliest longitudinal progression on pRNFL GPA event analysis. Outcome Measures Correlation of OCT event change analysis with intraocular pressure (IOP), clinical variables, and baseline thickness of the pRNFL and mGCIPL. Results IOP, baseline pRNFL thickness, baseline mGCIPL thickness and systemic hypertension were associated with location of first progression. Eyes demonstrating earliest longitudinal progression on mGCIPL had significantly lower maximum-recorded pre-treatment IOP (mean difference: 3.90mmHg, 95%CI: 2.37-5.43; p Conclusion Clinical features, particularly pre-treatment IOP, influence whether structural glaucoma progression is detected earlier with mGCIPL or pRNFL imaging. These data support the utility of mGCIPL imaging in addition to pRNFL analysis for detection of glaucoma progression, particularly in patients with normal IOP.