To evaluate the thinning of circumpapillary retinal nerve fiber layer (cpRNFL) and macular ganglion cell-inner plexiform layer (mGCIPL) in primary open angle glaucoma (POAG) eyes with and without history of disc hemorrhage (DH).
Observational cohort study SUBJECTS: 39 eyes (34 subjects) with DH and 117 eyes (104 subjects) without DH from the Diagnostic Innovations in Glaucoma Study (DIGS) and the African Decent and Glaucoma Evaluation Study (ADAGES).
All participants had at least 1.5-years of follow-up with a minimum of 3 visits with bi-annual spectral-domain optic coherence tomography (SD-OCT) cpRNFL and mGCIPL thickness measurements and visual fields (VF). The rates of cpRNFL and mGCIPL thinning were calculated using mixed effects models. The dynamic range-based normalized rates of cpRNFL and mGCIPL were calculated and compared between the DH and non-DH groups.
Rates of cpRNFL and mGCIPL thinning RESULTS: The rate of mGCIPL thinning was significantly faster in the DH group compared to the non-DH group (-0.62 vs. -0.38 μm/year, P=0.024). The rate of cpRNFL thinning in the DH quadrant and rate of mGCIPL thinning in inferotemporal sector in the DH group were faster than the corresponding regions in the non-DH group after adjusting for intraocular pressure (IOP) and race (-1.33 vs. -0.58 μm/year, P=0.053, and (-0.82 vs. -0.44 μm/year, P = 0.048, respectively). In the DH group, the percent rate of loss was significantly faster with mGCIPL than cpRNFL (-1.59 vs. -1.31 %/year, P=0.046). mGCIPL thinning rates were weakly associated with MD slope, VFI slope, and GPA (R = 3.6%(P=0.058), R=2.4%(P=0.096), and R= 5.2%(P=0.073), respectively). The area under operating receiver curves for VF progression based on Guided Progression Analysis was 0.75 for mGCIPL and 0.56 for cpRNFL in the DH group.
In our study, the rate of mGCIPL and cpRNFL thinning was faster in DH eyes than non-DH eyes. mGCIPL showed higher proportional rates of thinning and greater association with functional progression compared to cpRNFL. In addition to cpRNFL, clinicians should consider incorporating mGCIPL imaging to monitor glaucoma progression, especially in glaucoma eyes with DH.