Consider Charles Bonnet syndrome in glaucoma patients even if visual acuity is still good
June 30, 2021

Consider Charles Bonnet syndrome in glaucoma patients even if visual acuity is still good

Charles Bonnet syndrome (CBS) describes the presence of complex visual hallucinations with retained insight in the unreal nature of the phenomenon in patients with visual function loss, and no other neurological or psychiatric disorders.

CBS has been found to affect between 2.8% and 20.1% of glaucoma patients, with higher rates in individuals with bilateral low visual acuity or extensive visual impairment (1). However, CBS has also been described in glaucoma patients with visual field loss but maintained visual acuity (2,3). Approximately one third of all patients with CBS feel distress about their symptoms, and negative experience of CBS is correlated to unawareness about CBS at the onset of symptoms (4).

Ophthalmologists and other health-care providers need to be familiar with CBS in patients with glaucoma and should preventively talk about CBS with their glaucoma patients even when visual acuity is unaffected.
Contributor: Dorothea Peters, MD, PhD, Eye Clinic at Skane University Hospital and Department of Clinical Sciences Malmö, Ophthalmology, Lund University, Sweden


  1. Subhi Y, Schmidt DC, Bach-Holm D, Kolko M, Singh A. Prevalence of Charles Bonnet syndrome in patients with glaucoma: a systematic review with metaanalyses. Acta Ophthalmol. 2021;99(2):128-133.
  2. Madill SA, ffytche DH. Charles Bonnet syndrome in patients with glaucoma and good acuity. Br J Ophthalmol. 2005;89(6):785-786; author reply 786.
  3. Lomo T, Singh A, Peters D. Three cases of Charles Bonnet Syndrome in patients with advanced glaucomatous visual field loss but preserved visual acuity. Acta Ophthalmol. 2020. Sep 11. doi: 10.1111/aos.14620. Online ahead of print.
  4. Cox TM, ffytche DH. Negative outcome Charles Bonnet syndrome. Br J Ophthalmol. 2014;98(9):1236-1239.

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