In Vivo anterior Optic Nerve Head changes as a function of Visual Field loss in Glaucoma

Abstract

AbstractPurposeTo correlate regional measures of prelamina (preL) depth and thickness, anterior lamina cribrosa (LC) depth and nerve fibre layer (NFL) thicknesses with change in visual field sensitivity in primary open angle glaucoma, using enhanced depth imaging optical coherence tomography (OCT).MethodsThree‐dimensional image datasets were acquired as 20° scans centred on the optic nerve head (ONH) of glaucoma (n=111) and control (n=39) eyes, using a custom built OCT at 1040nm (spectral bandwidth 70nm). ONH measurements of regional (superior [S], inferior [I], nasal [N], temporal [T], and central [C]) preL and anterior LC depth were performed using Bruch’s membrane opening as a reference plane. PreL thickness was calculated from these surface measures. Border (above BMO) and peripapillary (pp) NFL were also measured. Intraclass correlation coefficients (ICC) were used to determine intra‐session repeatability.ResultsPreL depth (S: r=0.339, I: r=0.363, and N: r=0.317; p<0.001, T: r=0.219, p=0.007, central: r=0.202, p=0.013) and anterior LC depth (S: r=0.232, p=0.006, I: r=0.229, p=0.006, N: r=0.246, p=0.009, T: r=0.169, p=0.04, central: r=0.226, p=0.006) significantly increased with increasing VF loss in all ONH regions. PreL thickness significantly decreased with increasing VF loss in all ONH regions, (S: r=‐0.295 and I: r=‐0.346; p<0.001, N: r=‐0.218, p=0.026, temporal: r=‐0.177, p=0.031), except for the centre (r=‐0.106, p=0.199). ICCs >0.9 were calculated for all ONH measures and intra‐session differences in the ONH parameters were not identified within triplicate image datasets (p>0.05). BNFL and ppNFL thicknesses significantly decreased with VF loss (p<0.001).ConclusionsSignificant correlations were found between preL depth and thickness, and anterior LC depth with VF function, indicating that these quantitative (and repeatable) measures are useful in monitoring glaucomatous optic neuropathy.