Effects of optic nerve head structures on retinal nerve fiber layer defects in primary open angle glaucoma eyes. Analyses using ROTA.

PURPOSE

To elucidate associations between optic nerve head (ONH) structures and the retinal nerve fiber layer optical texture analysis (ROTA)-detected retinal nerve fiber layer defects (RNFLDs) in primary open angle glaucoma (POAG) eyes.

DESIGN

Prospective cross-sectional observational study

PARTICIPANTS

This study enrolled 136 eyes of 109 POAG patients.

METHODS

All participants underwent comprehensive ophthalmologic examinations including standard automated perimetry and swept-source optical coherence tomography (SS-OCT). Two independent graders assessed ROTA images for the presence, location, and width of RNFLDs. Multi-variable linear mixed-effect model was used to investigate factors independently associated with ROTA-detected RNFLDs. Explanatory variables were systemic and ocular factors such as age, axial length (AXL), SS-OCT-derived ONH structural parameters such as Bruch membrane opening-centered circum-papillary retinal nerve fiber layer thickness (cpRNFLT) and gamma zone area, and average visual field sensitivity (1/Lambert) (VFS).

MAIN OUTCOME MEASURES

Width and number of RNFLD.

RESULTS

RNFLD detection rates by ROTA were 86.8% overall, and 69.0% and 94.7 % in the early and moderate stages of POAG eyes, and 86.5% and 87.2 % in the highly (AXL>26.0 mm) and non-highly myopic eyes, respectively. Summed width of RNFLD per eye was positively correlated with gamma-zone area area (P=0.0007) and negatively correlated with age, cpRNFLT and VFS(P=0.0111, 0.0001, 0.0124), while the number of RNFLD per eye negatively with age, cpRNFLT and VFS(P=0.0153, 0.0029, 0.0007).

CONCLUSIONS

The ROTA-detected extent of axonal damage was associated with ONH structural change represented by gamma zone area in POAG eyes after adjustment for other possible confounding factors.