Tip of the Month
Publishing date: July 2020
Tip Editors: Frances Meier-Gibbons, Humma Shahid, Karl Mercieca, Francisco Goni
Tip reviewer: Roger Hitchings
The Science behind the Tip
The diagnosis of glaucoma can be missed in patients with small optic discs (1). In such patients, relative crowding of the retinal nerve cell layer can mean that an optic disc may look relatively normal in an eye with significant glaucoma (2).
Furthermore, such patients may be significantly hyperopic meaning that an visual field defect may be ascribed to optical effects of their hyperopic spectacle correction. Additionally, these patients may be at higher risk of chronic angle closure with intermittent pressure spikes (3). It is important to have a careful look at these patients and not ascribe glaucomatous field loss to other causes (4).
Contributor: James F Kirwan, Portsmouth Hospitals NHS Trust, UK
1. Nixon GJ, Watanabe RK, Sullivan-Mee M, DeWilde A, Young L, Mitchell GL. Influence of Optic Disc Size on Identifying Glaucomatous Optic Neuropathy. Optom Vis Sci. 2017 Jun;94(6):654-663.
2: Hoffmann EM, Zangwill LM, Crowston JG, Weinreb RN. Optic disk size and glaucoma. Surv Ophthalmol. 2007 Jan-Feb;52(1):32-49. Review.
3: Shen L, Melles RB, Metlapally R, Barcellos L, Schaefer C, Risch N, Herrinton LJ, Wildsoet C, Jorgenson E. The Association of Refractive Error with Glaucoma in a Multiethnic Population. Ophthalmology. 2016 Jan;123(1):92-101.
4: Garway-Heath DF, Ruben ST, Viswanathan A, Hitchings RA. Vertical cup/disc ratio in relation to optic disc size: its value in the assessment of the glaucoma suspect. Br J Ophthalmol. 1998 Oct;82(10):1118-24.