I once had a patient state very calmly that there was an army in her backyard filming a movie. Her family was quite concerned and worried that she was developing dementia or a serious mental illness. Fortunately neither was the case. These “hallucinations” were caused by a condition called the Charles Bonnet Syndrome.
This syndrome occurs in those with limited vision. In my experience, it is generally seen in patients with severe macular degeneration but recently a patient came in with this who had suffered a stroke affecting his vision on one side. Only 10-40% of those with severe vision loss experience the syndrome. Charles Bonnet was a Swiss philosopher who first described these visual hallucinations in 1760 after observing his grandfather who was going blind from cataracts.
The mechanism is thought to be due to the brain filling in for the reduced visual input. The episodes last from seconds to minutes and are of variable frequency. About 18 months after the onset they just usually gradually disappear. The most common type involves faces of people but animals or plants may also be seen. The images appear smaller than in real life. Another hallmark is that vision is the only sense involved so there are no associated abnormal sounds or smells.
What to do if you yourself or a family member are experiencing this syndrome? First be sure to have a thorough eye examination to see if there are any treatment options for the vision loss. If none are available, then reassurance from family and friends about what is real and what is not is helpful for the patient. Hopefully the above explanation will set all involved at ease.
Dr. Martha Jay is an Eye Physician & Surgeon (Ophthalmologist) practicing at Lakeshore Eye Care Professionals with offices in Mequon & Saukville, Wisconsin. She specializes in blade-free LASIK and small incision cataract surgery.
For more eye care information, call 262-241-1919 or visit www.LakeShoreVision.com.