Correlation between retinal ganglion cell count and morpho‐functional parameters in glaucoma

Abstract

AbstractPurpose To evaluate the correlation between retinal ganglion cell (RGC) count and morpho‐functional parameters provided by spectral‐domain optical coherence tomography (SD‐OCT) and standard automated perimetry (SAP)Methods 52 eyes evaluated for open angle glaucoma underwent a complete ophthalmologic examination including SAP and SD‐OCT evaluation of retinal nerve fiber layer (RNFL) thickness and macular ganglion cell complex (GCC). RGC counts were obtained using a previously derived algorithm proposed by Medeiros et al. Patients were divided into 3 groups according to glaucoma severity staged by Glaucoma Staging System 2: suspects (stage 0‐border), early (stage 1‐2) and manifest glaucoma (stage 3‐4‐5)Results Average RGC count estimate was 933803±132506 in suspects, 685583±158345 in early and 385316±185374 in manifest glaucoma (p<0.001). The same trend was noticed for the considered parameters, even if the major loss was found between early and manifest glaucoma in functional data (MD and PSD) and between suspects and initial glaucoma in structural data (RNFL and GCC). RGC count showed very poor correlation with PSD in all groups (r<‐0.3), a progressively increased correlation with MD according to glaucoma severity (r>0.3 in suspects, r>0.9 in manifest glaucoma), a moderate correlation with RNFL (r>0.6) and GCC (r>0.5) in all groupsConclusion A substantial loss of RGCs is detectable in all groups and proportional to glaucoma stages. Structural evaluation of optic nerve (RNFL) and inner macular retina (GCC) can provide a useful diagnostic tool in all stages while SAP is well correlated only to substantial loss of RGC. Macular RGC are involved in early glaucoma loss