Relationship Between Location of Retinal Nerve Fiber Layer Defect and Curvature of Retinal Artery Trajectory in Eyes With Normal Tension Glaucoma.

PURPOSE

To quantify the degree of curvature of the retinal artery trajectory (RAT) and to investigate the relationship between the curvature and the location of a retinal nerve fiber layer defect (NFLD) in eyes with normal tension glaucoma (NTG).

METHODS

This was a retrospective observational study of 88 eyes of 88 NTG patients who had a wedge-shaped NFLD. The retinal artery trajectory and the position of the NFLD were assessed in the fundus photographs. The course of the supra and infratemporal retinal arteries were marked on a color fundus photograph and fitted to a second degree polynomial curve (ax[x]/100 + bx + c) using ImageJ. The coefficient "a" was used for the curvature of the trajectory. The proximity of the NFLD to the fovea (supra-NFLD angle, infra-NFLD angle) was determined by two methods. The relationship between the RAT and the supra-NFLD angle and the infra-NFLD angle was determined by linear regression analyses.

RESULTS

Fifty-six eyes had a supratemporal NFLD and 69 eyes had an infratemporal NFLD. The steepness of the RAT was significantly correlated with the supra-NFLD angle 1 (R = -0.27, P = 0.041) and angle 2 (R = -0.28, P = 0.040), but not with the infra-NFLD angle 1 (R = -0.06, P = 0.61) and angle 2 (R = -0.21, P = 0.078).

CONCLUSIONS

The supratemporal NFLDs were located closer to the fovea in eyes with the retinal artery closer to the fovea in NTG patients. The steepness of the trajectory of the temporal retinal artery can be one predictor of the proximity of the NFLD to the fovea.