Tip of the Month
Publishing date: December 2019
Tip Editors: Frances Meier-Gibbons, Humma Shahid, Karl Mercieca, Francisco Goni
Tip reviewer: Roger Hitchings
The Science behind the Tip
Axonal loss decreases the volume of the disc, and if loss is concentrated in one area without significant gliosis, cupping without pallor can result. But axonal loss from other causes also decreases the volume of the disc (1,2).
An often unrecognized red flag is that there can be significant visual field dysfunction from conduction block caused by a compressive lesion, without enough axonal loss to cause disc pallor (3). In a disc with physiological cupping, it may be even easier to mistake the visual field loss as being related to glaucoma.
Contributor: Leonard A. Levin, Montreal, Canada
1. Bianchi-Marzoli S, Rizzo JF, 3rd, Brancato R, Lessell S. Quantitative analysis of optic disc cupping in compressive optic neuropathy. Ophthalmology 1995;102(3):436-40.
2. O'Neill EC, Danesh-Meyer HV, Kong GX, et al. Optic disc evaluation in optic neuropathies: the optic disc assessment project. Ophthalmology 2011;118(5):964-70.
3. Danesh-Meyer HV, Papchenko T, Savino PJ, et al. In vivo retinal nerve fiber layer thickness measured by optical coherence tomography predicts visual recovery after surgery for parachiasmal tumors. Invest Ophthalmol Vis Sci 2008;49(5):1879-85.