Relationship between ganglion cell-inner plexiform layer and optic disc/retinal nerve fibre layer parameters in non-glaucomatous eyes.

Aims: To determine the relationship between macular ganglion cell-inner plexiform layer (GC-IPL) thickness and optic disc/retinal nerve fibre layer (RNFL) parameters in non-glaucomatous eyes measured by spectral-domain optical coherence tomography (SD-OCT).

Methods: 491 non-glaucomatous Chinese aged 40-80 years were recruited from a population-based study and underwent standardised ophthalmic examination. SD-OCT was used to measure GC-IPL thickness, optic disc parameters and RNFL thickness. Univariate and multiple linear regression analyses were performed to assess the association between GC-IPL and optic disc/RNFL parameters.

Results: In univariate analyses, all RNFL parameters and rim area were significantly correlated with all macular GC-IPL parameters (p<0.001, r=0.12-0.56). In multiple regression analyses, after adjusting for age, gender, disc area, signal strength and axial length, average RNFL thickness (per µm decrease) was most strongly correlated with average GC-IPL thickness (β=-0.30, standardised β=-0.499, p<0.001) compared with other optic disc/RNFL parameters.

Conclusions: Our study demonstrated only fair correlations between macular GC-IPL and optic disc/RNFL parameters measured by SD-OCT. This information is important for further evaluation of macular GC-IPL thickness as an additional marker in detecting glaucomatous damage and progression.