Retinal Nerve Fiber Layer Optical Texture Analysis: Involvement of the Papillomacular Bundle and Papillofoveal Bundle in Early Glaucoma.

Purpose

To apply retinal nerve fiber layer (RNFL) optical texture analysis (ROTA) in eyes with early glaucoma to investigate (1) the pattern of RNFL defects, (2) how often the papillomacular bundle and papillofoveal bundles are involved, and (3) the association between papillomacular and papillofoveal bundle defects and visual field (VF) sensitivity abnormalities.

Design

Cross-sectional study.

Participants

Two hundred four eyes with early glaucoma (VF mean deviation, ≥ -6 dB) with RNFL defects from 171 consecutively enrolled patients with glaucoma.

Methods

All eyes underwent 24-2 VF testing and OCT for ROTA. The borders of RNFL defects were delineated from ROTA, and the involvement of the arcuate bundle, papillomacular bundle (i.e., bundles from the macula, excluding the fovea), and papillofoveal bundle (i.e., bundles from the fovea) was determined for each eye. Multilevel logistic regression analysis was applied to evaluate the structure-function association.

Main outcome measures

Proportions of eyes with papillomacular or papillofoveal bundle defects.

Results

Of the 204 eyes, 71.6% and 17.2% demonstrated RNFL defects involving the papillomacular and papillofoveal bundles, respectively; 25.0% showed arcuate bundle defects without involvement of papillomacular or papillofoveal bundles. The pattern of RNFL defects was diverse; the most common was concomitant involvement of the inferior arcuate bundle and the inferior papillomacular bundle (20.6%). Papillomacular or papillofoveal bundle defects were not associated with VF defects (i.e., with ≥ 3 contiguous locations with abnormal VF sensitivity in the pattern deviation probability plot) in the corresponding hemifield, although VF sensitivity of any 1 of the central 4 VF locations of the 24-2 test, which were within the macula, was more likely to be abnormal (P < 0.05 in the pattern deviation probability plot; odds ratio, 12.5; 95% confidence interval, 7.0-22.5) when the VF stimulus was projected onto a papillomacular or papillofoveal bundle defect than that projected onto an intact papillomacular or papillofoveal bundle.

Conclusions

Contrary to the conventional notion that the fovea and macula are not affected until the late stages of glaucoma, papillofoveal and papillomacular bundle defects were common in early glaucoma, and they were associated with central VF sensitivity loss at the corresponding VF test locations.