WHEN IS A VISUAL HALLUCINATION NOT A CAUSE FOR ALARM? By Dr. Martha Jay, Ophthalmologist at Lakeshore Eye Care Professionals with offices in Mequon & Saukville, Wisconsin
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. Macular degeneration is the leading cause of legal blindness for people over 65, but 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 from the eye. The episodes can last from seconds to minutes, occur rarely or be more frequent. Usually about 18 months after the onset they just gradually disappear. The most common type of hallucination 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 involved. As with the patient who “saw” the army in her backyard, the images rarely concern the patient but are worrisome to their family members. Hopefully the above explanation will set all involved at ease.
Dr. Martha Jay is a Board Certified ophthalmologist specializing in medical and surgical eye care including blade-free iLASIK and small incision cataract surgery with premium lens implants.
For more eye care informati0n, call 262-241-1919 or visit www.LakeShoreVision.com