Retinal nerve fiber layer thickness and radial peripapillary capillaries density in myopic adults with optical coherence tomography angiography

Abstract

Purpose: To evaluate retinal nerve fiber layer thickness (RNFLT) and radial peripapillary capillaries (RPC) density in adults with different degrees of myopia using optical coherence tomography angiography (OCTA) and explore their relationship with ocular factors, such as axial length (AL) and disc area.

Methods: A total of 188 subjects were included in this cross-sectional study. The eyes were divided into four groups according to AL. OCTA was used for the assessment of RNFLT, RPC density, and other optic disc measurements, such as disc area. One-way analysis of variance was performed to compare differences between four groups, and P value < 0.01 was considered significant.

Results: The RNFLT was significantly thinner in high myopia (HM) group at inferior nasal (IN) quadrant (P = 0.004) than low myopia (LM) group, but thicker at temporal inferior (TI) quadrant (P = 0.006). The RPC density of nasal superior (NS) quadrant, nasal inferior (NI) quadrant, and inferior nasal (IN) quadrant significantly decreased as AL increasing. By simple linear regression analysis, the inside disc RPC (iRPC) density tended to be correlated significantly with AL (0.3997%/mm, P < 0.0001). Peripapillary RPC (pRPC) density was in significant correlation with AL (-0.2791%/mm, P = 0.0045), and peripapillary RNFLT (pRNFLT) was in significant correlation with disc area (0.2774%/mm², P = 0.0001).

Conclusion: RNFLT and RPC density were closely associated with AL and disc area. They might be new indexes in assessing and detecting myopia development via OCTA.

Keywords: Optic disc; Optical coherence tomography angiography (OCTA); Radial peripapillary capillaries (RPC); Retinal nerve fiber layer (RNFL).

Fig. 1

Pictorial representation of the structure and capillary plexus of optic disc. a optic disc, b retinal nerve fiber layer, c radial peripapillary capillaries, d superior nasal (SN), nasal superior (NS), nasal inferior (NI), inferior nasal (IN), inferior temporal (IT), temporal inferior (TI), temporal superior (TS), superior temporal (ST) quadrants

Fig. 2

Scatter plot of simple linear regression between (A) peripapillary retinal nerve fiber layer (RNFL) thickness and axial length (AL) (P = 0.066), (B) whole radial peripapillary capillaries (RPC) density and AL (P = 0.2223), (C) inside disc RPC density and AL (P < 0.0001), (D) peripapillary RPC density and AL (P = 0.0029), (E) peripapillary RNFL thickness and disc area (P = 0.0001), (F) whole RPC density and disc area (P = 0.8313), (G) inside disc RPC density and disc area (P < 0.001), (H) peripapillary RPC density and disc area (P = 0.6064)