Novel area-based optic nerve head parameter to distinguish glaucoma from non-glaucomatous retinal nerve fiber layer defect in branch retinal vein occlusion.

PURPOSE

The purpose of this study was to assess the diagnostic ability of the new area-based parameter retinal nerve fiber layer to disc ratio (RDR) for discriminating between glaucoma and non-glaucomatous retinal nerve fiber layer defects (RNFLDs).

METHODS

This retrospective cross-sectional study included 42 branch retinal vein occlusion (BRVO) eyes with RNFLD, 42 open-angle glaucoma (OAG) eyes, and 42 healthy control eyes that were matched with optic disc size. The RDR, peripapillary retinal nerve fiber layer thickness (pRNFLT), Bruch's membrane opening-minimum rim width (BMO-MRW), and Bruch's membrane opening-minimum rim area (BMO-MRA) were analyzed. The areas under the receiver operating characteristic curves (AUCs) were calculated for each parameter.

RESULTS

The OAG and BRVO groups had similar global pRNFLT (87.57 ± 7.07 µm and 89.71 ± 12.21 µm, respectively), but these were thinner than those of the healthy group (102.71 ± 8.95 µm, p < 0.001 and p < 0.001, respectively). RDR was lowest in the BRVO group (0.755 ± 0.121, p < 0.001) and highest in the OAG group (1.111 ± 0.145, p < 0.001). Global BMO-MRW was significantly lower in the OAG group (194.36 ± 23.09 µm) than in the BRVO (269.69 ± 42.77 µm, p < 0.001) and healthy (273.48 ± 30.92 µm, p < 0.001) groups. Total BMO-MRA of the OAG group (0.88 ± 0.12 mm) was significantly lower than that of the BRVO (1.32 ± 0.19 mm, p < 0.001) and healthy (1.30 ± 0.21 mm, p < 0.001) groups. AUC for discriminating between the OAG and BRVO was 0.986 for total BMO-MRA and 0.970 for RDR (p = 0.192).

CONCLUSION

In clinical practice, RDR may perform well as a parameter to distinguish between glaucoma and non-glaucomatous RNFLD.