I will try to write about one interesting eye case that I see each day. (Though I have been guilty of not updating this for a long time, not for lack of cases, but due to my own laziness.) The purpose is to provide education of eye diseases, vision function and eye care to the public, and maybe to students who study optometry.

You know that sometimes unusual cases happen in clusters, like when you see three central serous retinopathy or two posterior polymorphous corneal dystrophy patients on the same day? Obviously if you are a tertiary referral center then that can be common, but for a primary eye care practice, it can be striking. I just saw two patients with visual hallucination today, that’s about the total number of hallucination cases I have ever seen since starting this primary eye care clinic 2 years ago.

68 year old lady stated she was seeing a woman in old fashioned clothes climbing a ladder in her living room, and specifically the woman had very hairy legs. She knew it was a hallucination, and went to ED for it. She was hospitalized for a few days for stroke workup including brain CT and then MRI; saw a cardiologist and then a neurologist. She told me 5 doctors were working on this for her. She had a few systemic issues including diabetes but she was not taking any medications as she stopped all these sometime ago. Anyway it turns out her visual hallucination is most likely a result of Charles Bonnet Syndrome, since her left eye has developed a dense cataract with a visual acuity of 20/80, and this moderate vision loss led to visual release hallucination. She is going to call her cataract surgeon for an evaluation.

At 3 PM a 59 old guy walked in per his cardiologist’s urgent referral. Cardiologist told me it’s a loss of vision post operation, so my immediate thought went to optic neuropathy or central retinal artery occlusion (CRAO) or something along that line. His left eye had a stick penetrating as a child and could never see much since then. Right eye was the good eye. So I assumed that his left eye was not seeing well now. So when he read 20/15 on the eye chart, I almost threw him out- this guys sees better than a 30 year old, why wasting my time? On further questioning, he admitted it’s not that the right eye was not seeing well, rather his left eye started seeing too much that bothered him. This made no sense. It was only in hindsight that I realized why he was being so vague about his symptoms. First, hallucinations are things that do not follow logic or make sense; 2nd, people in general feel embarrassed when talking about their hallucinations for fear they will be thought of as crazy. Eventually I got the story out of him. Last Monday he had a heart surgery and was released home last Friday, when he started noticing seeing colors like through prism glasses and all sorts of shapes like pumpkin and so on. He noticed these in his weak left eye but also in the normal right eye. Only when he closed both eyes did they go away. This was concerning to him because when he talked with people he would see these things on people’s faces and made it hard for him to focus.

You may guess the rest of the eye exam. Yes he had completely normal eye health in the right eye, and left eye was aphakic (having no lens) and had glaucoma but he’s seeing an outside eye doctor every 3 months for this and his eye pressure today was 16 (normal).

Could it be Charles Bonnet after so many years of poor vision in that left eye? Maybe. Was it a coincidence that he started this after a major surgery? Not sure. Since he did take multiple medications (quite a few medications including some hypertension meds, antidepressants, even some antibiotics are associated with visual hallucinations), and it’s after a heart surgery, I referred him to see a neurologist to rule out other causes of hallucinations.

Charles Bonnet Syndrome was first described by Charles Bonnet, a Swiss philosopher, who witnessed his near-blind grandfather seeing things that were not there. These hallucinations happen because of lack of visual input to the brain to suppress certain spontaneous firing of visual cortex neurons. Any form of visual loss may cause it, but commonly conditions such as age-related macular degeneration, glaucoma, dense cataract, etc are associated with Charles Bonnet Syndrome. By the way, with both my patients today visual hallucination was not associated with auditory or other sensory hallucinations, and patients were aware that these things they saw were not real. These were additional criteria for Charles Bonnet Syndrome.