Researchers have identified a topographic feature of the retina that may help clinicians better preserve their glaucoma patients’ functional vision: the papillomacular bundle of the retinal nerve fiber bundle.

The study included 23 eyes of 21 glaucoma patients (mean age 61.3; male to female ratio 9:12). Baseline characteristics were a mean deviation of -19.9dB on Humphrey field analyzer,  BCVA 20/20 or more and a remaining papillomacular bundle (PMB) with a maximum width ≤ half the vertical disc diameter.

The researchers performed OCT and “measured the frequency of remaining PMB at 10µm intervals along a vertical line intersecting the disc center and fovea line (DFL) at its midpoint.” They found that, in averaged en face images, residual PMB area “appeared as a high-intensity region above the disc center and fovea line.” Residual PMB was most often found in the 830µm to 870µm area above the disc center and fovea line. They noted that the AUC for identifying decreased BCVA was highest for ganglion cell complex thickness (cutoff: 87.5µm).

The authors concluded that, in glaucoma patients, certain areas of PMB were associated with visual acuity in wide-scan, en face OCT images. “It may be possible to identify visual impairment during glaucoma treatment by measuring this area,” they said.

Takahashi N, Omodaka K, Kikawa T, et al. Association between topographic features of the retinal nerve fiber bundle and good visual acuity in patients with glaucoma. Curr Eye Res. April 16, 2021. [Epub ahead of print].