CBS - Seeing What's Not Really There: Strategies for Life, Living Well With Vision Loss
By Donna LeBlanc, Certified Vision Rehabilitation Therapist
December 1, 2007
Have you heard capable people talk about seeing things that are not there, that they have “phantom vision” (Lighthouse)? Perhaps they have Charles Bonnet Syndrome (or CBS for short). CBS is “a term used to describe the situation when people with sight problems start to see things which they know aren’t real” (RNIB). This occurs in people of all ages who have a sound mind but have low vision, which means acuity of 20/70 or less with best correction.
People with CBS have poor vision but can very clearly see certain images which they know are not real. According to a paper, presented at the International Conference on Low Vision ‘99 by Lylas Mogk, MD et al., called “Charles Bonnet Syndrome in Adults with Vision Impairment” common images seen are patterns (i.e. grids and squares), flowers, people, animals or trees. For example, a client who has age related macular degeneration said to me, “I see plaid all over my white walls and floors.” She then laughed and said, “I’m so tired of that plaid pattern. I want my white walls back!” These images are interesting but usually not threatening or frightening and many people get used to them and no longer find they interfere (AMD).
Many people over 60 have problems with their sight such as cataract, macular degeneration, glaucoma and diabetic retinopathy. While CBS can affect people of any age after a significant loss of vision, it most often affects people who have lost their sight later in life. These visual hallucinations usually stop within a year to 18 months.
In 1760 a Swiss naturalist named Charles Bonnet noticed that his grandfather started to see “amusing and magical visions.” Bonnet’s grandfather was quite sane; he knew the strange sights were all in his mind, there were no other signs of mental illness or dementia. Charles Bonnet encountered the same thing himself when he was older and experiencing vision loss.
Problems can occur when Bonnet Syndrome is mistakenly thought to indicate mental illness, stroke, Parkinson’s disease, Alzheimer’s or other dementias. Family, friends, health professionals and sometimes the individual with the vision loss start to believe these visual images are a sign of the beginning of serious physical, cognitive or mental problems. People with CBS are not more likely to develop any of these health problems than other people (RNIB).
There have been times when some of the older adults I work with have told me that they were getting concerned because they, and their families, were worried about these hallucinations. I share resource information about CBS and encourage them to discuss this possibility with their families and doctors. It is critical to explore Charles Bonnet Syndrome as a possible explanation.
(Charles Bonnet Syndrome resources include: www.amd.org, www.lighthouse.org, www.rnib.org.uk, Macular Degeneration, the Complete Guide to Saving and Maximizing your Sight by Mogk, Lylas G. & Marja Mogk, published by Ballentine Books and the paper mentioned above in Vision Rehabilitation: Assessment, Intervention sand Outcomes, published by Swets & Zeitlinger.)
Perkins Outreach Services for Ages 55 and Older, Outreach@Perkins.org, 617-972-7643