Published: 01 September 2022

Who is Charles Bonnet?  He was a Swiss naturalist, philosopher, and biologist (1720-1793) who first described the hallucinatory experiences of his 89-year-old grandfather, who was nearly blind in both eyes from cataracts.  Charles Bonnet Syndrome is now the term used to describe simple or complex hallucinations in people who have impaired vision.  

Symptoms

People who experience these hallucinations know they aren't real.  These hallucinations are only visual, and they don't involve any other senses. These images can be simple patterns or more complex, like faces or cartoons.  They are more common in people who have retinal conditions that impair their vision, like macular degeneration, but they can occur with any condition that damages the visual pathway.  The prevalence of Charles Bonnet Syndrome among adults 65 years and older with significant vision loss is reported to be between 10% and 40%.  This condition is probably under reported because people may be worried about being labeled as having a psychiatric condition. 

Causes

The causes of these hallucinations are controversial, but the most supported theory is deafferentation, which in this case is the loss of signals from the eye to the brain; then, in turn, the visual areas of the brain discharge neural signals to create images to fill the void.  This is similar to the phantom limb syndrome, when a person feels pain where a limb was once present.  In general, the images that are produced by the brain are usually pleasant and non-threatening.

Treatment and prognosis

If there is a reversible cause of decreased vision, such as significant cataract, then once the decreased vision is treated, the hallucinations should stop.

There is no proven treatment for the hallucinations as a result of permanent vision loss but there are some techniques to manage the condition.  Give these a try if you have Charles Bonnet Syndrome.

• Talking about the hallucinations and understanding that it is not due to mental illness can be reassuring.
• Changing the environment or lighting conditions.  If you are in a dimly lit area, then switch on the light and vice versa. 
• Blinking and moving your eyes to the left and right and looking around without moving your head have been reported as helpful.
• Resting and relaxing.  The hallucinations may be worse if you are tired or sick.
• Taking antidepressants and anticonvulsants have been used but have questionable efficacy. 

Over time, the hallucinations become more manageable and can decrease or even stop after a couple of years.

If you experience any of these symptoms, please get evaluated by your eye doctor to make sure there is not a treatable eye condition.  Don’t be embarrassed or ashamed—your issue is likely caused by a physical disturbance and we are here to help!

Article contributed by Jane Pan

Published: 25 August 2022

We commonly see patients who come in saying that their eyes are bleeding.

The patient is usually referring to the white part of their eye, which has turned bright red. The conjunctiva is the outermost layer of the eye and contains very fine blood vessels.  If one of these blood vessels breaks, then the blood spreads out underneath the conjunctiva. This is called a subconjunctival hemorrhage.

A subconjunctival hemorrhage doesn't cause any eye pain or affect your vision in any way. Most of the time, a subconjunctival hemorrhage is asymptomatic.  It is only noticed when looking at the mirror or when someone else notices the redness of the eye.  There should not be any discharge or crusting of your lashes.  If any of these symptoms are present, then you may have another eye condition that may need treatment.  

What causes a subconjunctival hemorrhage?  The most common cause is a spontaneous rupture of a blood vessel.  Sometimes vigorous coughing, sneezing, or bearing down can break a blood vessel.  Eye trauma and eye surgery are other causes of subconjunctival hemorrhage.  Aspirin and anticoagulant medication may make patients more susceptible to a subconjunctival hemorrhage but there is usually no need to stop these medications.  

There is no treatment needed for subconjunctival hemorrhage.  Sometimes there may be mild irritation and artificial tears can be used.  The redness usually increases in size in the first 24 hours and then will slowly get smaller and fade in color.  It often takes one to two weeks for the subconjunctival hemorrhage to be absorbed.  The larger the size of the hemorrhage, the longer it takes for it to fade.

Having a subconjunctival hemorrhage may be scary initially but it will get better in a couple of weeks without any treatment. However, redness in the eye can have other causes, and you should call your eye doctor, particularly if you have discharge from the eye.

Article contributed by Dr. Jane Pan