Age-Related Eye Diseases and Charles Bonnet Syndrome in AREDS2
September 10, 2021
Written by Bruce P. Rosenthal OD, FAAO,Chief of Low Vision Services, Lighthouse Guild
- Over a 10-year period, participants in the AREDS2 study were more likely to report symptoms of Charles Bonnet syndrome (CBS) if they also had late AMD, cataract surgery, or depression (without cognitive impairment).
- The authors conclude that clinicians should be aware of CBS in the visually impaired population and be proactive about discussing it — both to explore whether a patient has experienced CBS and to explain the potential for CBS, given their eye condition.
Eye care clinicians are well versed in the findings of the multicenter, randomized Age-Related Eye Disease Study (AREDS2) clinical trial. The AREDS2 study was notable for comprehensive eye examinations, data on cataract surgery, treatment for age-related macular degeneration (AMD), as well as to evaluate cognitive impairment. It is fortunate that the authors were able to access the 10-year-data from the AREDS2 in order to examine the association between Charles Bonnet syndrome (CBS) and late-stage AMD and cataract surgery.
The authors noted that this is most likely, the largest cohort of persons who have been evaluated for the prevalence of CBS-related visual hallucinations in persons with cataract, glaucoma, and age-related eye diseases. Previous studies were relatively small and reflected very diverse outcomes with a reported prevalence of 3% to 32%.
One area of emphasis is the literature, which suggests that CBS is often misdiagnosed by clinicians as psychosis or early dementia. However, retinal and low vision clinicians, for example, have long known about the relationship of AMD and CBS. In fact, the case history may often reflect questioning patients about experiencing hallucinations. Patients, in turn are not only very forthcoming in describing their hallucinations (eg, flowers, faces, small people walking across a table, or designs as the authors note) but relieved to get an explanation on what has been occurring. Many of these patients will, however, often complaint about an inability to control or eliminate the hallucinations. There have been, however, no accepted treatments in eliminating the intrusive and often disturbing hallucinations, but they frequently dissipate on its own.
From a low vision clinician’s viewpoint, CBS is predominantly prevalent in patients with AMD, especially those with a profound loss of vision (logMAR 1.0 (20/200) to logMAR 1.3 20/400 and logMAR 1.6 20/800 and worse). One other important area emphasized was depressive symptoms being associated with reporting CBS symptoms. Clinically we have added the PHQ2 (2015) two-question depression screening scale for clinicians. Social workers will follow-up if the patient screens positive. They will then evaluate the patient with the PQH9 to see if they meet the criteria for a depressive disorder.
The authors have brought to light and perhaps opened the door to the importance of educating the professional community about CBS among patients with eye conditions (including AMD, glaucoma, and cataracts) and depression. One way is to include CBS in lectures that are for not only incoming eye care interns1 and residents but other medical specialties as well.
1. Fontenot JL, Bona MD, Kaleem MA, et al.
Vision Rehabilitation Preferred Practice Pattern®. Ophthalmology. 2018;125(1):P228- P278. https://www.aaojournal.org/article/S0161–
Eyecare professionals should be aware of Charles Bonnet Syndrome (CBS), a phenomenon involving visual hallucinations in people with visual impairments. We examined prevalence of CBS among AREDS2 participants and its associations with age-related eye diseases.
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