Papillomacular bundle thickness is associated with visual acuity in proliferative diabetic retinopathy

To determine whether the papillomacular bundle thickness (PBT), measured as the retinal nerve fiber layer (RNFL) thickness at a point halfway between the fovea and the optic disc, is significantly associated with best-corrected visual acuity in eyes with proliferative diabetic retinopathy.

A retrospective observational study was conducted on patients with a history of proliferative diabetic retinopathy who presented to the Ambulatory Care Network Vitreoretinal Clinic at New York-Presbyterian Hospital at Columbia University Irving Medical Center between January and December 2023. One eye per patient was eligible for inclusion. The PBT was measured using pre-existing Cirrus OCT 512 × 128 macular cube scans. The ETDRS central subfield thickness (CST) was recorded from the Cirrus review software. Best-corrected visual acuity was obtained from the medical record and converted into an ETDRS letter score.

Forty-five patients were included. The mean ± SD ETDRS letter score, PBT, and CST were 58.6 ± 16.1 letters, 34.3 ± 13.9 μm, and 293.6 ± 107.0 μm, respectively. PBT was significantly correlated with visual acuity (r = 0.47; p = 0.001), while CST was not (p = 0.52). Linear regression of visual acuity on PBT yielded a coefficient of 0.55 (p = 0.001).

Thinning of the PBT is associated with decreased visual acuity in eyes with proliferative diabetic retinopathy. For every 2 micrometers of PBT thinning, there is an expected loss of approximately 1 ETDRS letter.