Correlations Between Retinal Ganglion Cell Layer Thickness and Morpho-Functional Parameters in Patients With Primary Open Angle Glaucoma

Abstract

Purpose: : to assess the retinal ganglion cell layer thickness by a spectral domain OCT and to evaluate the correlations with morphometric parameters as measured by confocal laser ophthalmoscopy and with functional parameters as measured by standard automated perimetry (SAP).

Methods: : 28 eyes from 16 primary open angle glaucoma patients were included in this cross sectional study. All patients were imagined by a spectral domain OCT (RTVue) and by a confocal scanning laser ophthalmoscope (Heidelberg Retina Tomograph, HRT 3); visual field was assessed by a Humprey Field Analyzer using a full threshold 30-2 program. The retinal ganglion cell layer (RGL) was measured by the RTVue, MM7 program. Rim area (RA), rim volume (RV), cup shape measure (CSM) and retinal fibre layer (RNFL) stereometric parameters were considered from the HRT 3 print-out; MD and PSD were considered from the HFA print-out for the global analysis, while mean superior and inferior visual field sensitivity were calculated for the sectorial analysis. The relationship between all functional and morphological parameters was assessed by Pearson’s correlation.

Results: : a significant correlation (p < 0.01) was found between RGL thickness and functional parameters in both global and sectorial analysis; a significant correlation (p < 0.01) was also found between RGL thickness and the most part of HRT sterometric parameters in both global and sectorial analysis .

Conclusions: : to our knowledge this is the first comparison between RGL thickness assessed by a spectral domain OCT and both functional and morphological parameters assed by SAP and HRT. Further studies are needed to determine the usefulness of this new approach for early diagnosis and follow up of primary open angle glaucoma patients.

Keywords: ganglion cells • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • perimetry