Quantification of peripapillary nerve fibre elevation and its association with axial length, optic disc tilt, and parapapillary atrophy area in young, healthy eyes.

Abstract

Eyes with peripapillary nerve fibre elevation (pNFE) may have a gap between the optic nerve papillary margin on colour fundus photography and Bruch's membrane opening on cross-sectional optical coherence tomography (OCT). This study was conducted to evaluate the quantification of the height of pNFE in young healthy eyes and examine the relationship between pNFE height and axial length. A prospective, observational, cross-sectional study was performed involving 117 right eyes. All participants (mean age 25.8 years) underwent comprehensive ophthalmologic examination involving axial length, fundus photography, and peripapillary and optic disc OCT. pNFE height was defined as the distance between the retinal surface plane and the upper edge of the pNFE in optic disc cross-sectional OCT images. Optic disc tilt was evaluated using a sine curve on retinal nerve fibre layer B-scan images. Parapapillary atrophy (PPA) area in colour fundus images was calculated using ImageJ and corrected using Bennett's formula. We evaluated relationships between pNFE height, axial length, optic disc papillary tilt, and PPA area using Spearman's correlation analysis. Sixty-five eyes had pNFE, with a mean pNFE height of 84.7 μm. pNFE height was significantly positively correlated with axial length (r = 0.32, p < 0.001), optic disc tilt (r = 0.25, p = 0.008), and PPA area (r = 0.27, p = 0.004). pNFE is not rare in young healthy eyes. Eyes with higher pNFE had a longer axial length and larger optic disc tilt and PPA area.