In markedly unilateral glaucoma, always rule out secondary causes before labelling the disease as primary

Primary open-angle glaucoma is generally bilateral, even if asymmetric. Therefore, a strongly unilateral presentation should raise suspicion for secondary mechanisms.(PMID: 34675001) Numerous entities, including pseudoexfoliation, post-traumatic angle recession, steroid exposure, uveitic disorders, drug-induced uveal effusion, ghost-cell glaucoma, lens-induced (phacolytic) glaucoma, or secondary to previous surgery, can selectively affect one eye and require targeted management.(PMID: 34675001, PMID: 19277212, PMID: 31357519, PMID: 27802552, PMID: 28805684) Unilateral glaucoma may also arise from elevated episcleral venous pressure, neovascularisation, uveal melanoma, or rare congenital or acquired angle anomalies as ectropion uveae or iridocorneal endothelial syndrome. (PMID: 34675001, PMID: 23953873, PMID: 31845811) Identifying these causes could prevent unnecessary treatment of the fellow eye and ensures appropriate, often aetiology-specific intervention.

References

• European Glaucoma Society Terminology and Guidelines for Glaucoma, 5th Edition. Br J Ophthalmol. 2021 Jun;105(Suppl 1):1-169. doi: 10.1136/bjophthalmol-2021-egsguidelines. PMID: 34675001.
• Schlotzer-Schrehardt U. Pseudoexfoliation syndrome: the most common identifiable cause of secondary open-angle glaucoma. J Glaucoma. 2009;18(2):123-125. doi:10.1097/IJG.0b013e318193c1b6. PMID: 19277212.
• Razeghinejad MR, Myers JS, Katz LJ. Angle recession glaucoma: clinical features and diagnosis. J Ophthalmic Vis Res. 2018;13(4):420-425. doi:10.4103/jovr.jovr14318. PMID: 31357519. • Hinkle DM, Zuravleff J, Pasquale LR. Medication-induced acute angle closure and uveal effusion: pathophysiology and management. Curr Opin Ophthalmol. 2017;28(2):181-187. doi:10.1097/ICU.0000000000000358. PMID: 27802552.
• Agrawal R, Deokar A, Mahendradas P, Khairallah M, Gupta V, Biswas J. Uveitic glaucoma: current concepts and management. Eye (Lond). 2017;31(3):377-390. doi:10.1038/eye.2016.288. PMID: 28805684.
• Rigi M, Alward WL, Lin SC. Pathophysiology and management of glaucoma associated with elevated episcleral venous pressure. Eye (Lond). 2014;28(4):522-528. doi:10.1038/eye.2013.266. PMID: 23953873.
• Pires I, Barbosa-Breda J, Castro A, Marques-Neves C, Figueiredo A. Iridocorneal endothelial syndrome: a comprehensive review and update. Surv Ophthalmol. 2020;65(5):512-528. doi:10.1016/j.survophthal.2019.12.005. PMID: 31845811.

Contributor: Jan Van Eijgen, MD PhD, FEBO Research Group of Ophthalmology (RGO), Department of Neurosciences, KU Leuven, Leuven, Belgium Department of Ophthalmology, University Hospitals UZ Leuven, Leuven, Belgium

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