Visual hallucinations in an elderly patient

The question: 

An elderly female patient presents at your practice with a small amount of visual field loss and unremarkable intraocular pressures. During history and symptoms, she reports that she often sees cyclists in the corner of her living room when she is completing her crossword. She also reports that she often misplaces cups of tea when at home. What are the potential diagnoses, and how would you manage the patient? 

OT’s panel says... 

Kevin Wallace: It sounds like this patient is suffering from Charles Bonnet Syndrome (CBS). In my experience the most important thing is to reassure the patient because it can be quite distressing. Patients with this sort of hallucination often worry that it is caused by a more significant medical condition. I would also want to have a good look at the internal eye to check for anything which requires treatment, or at least lifestyle modification, to reduce further vision loss. I would want to explain the visual field loss if possible – obviously just because the intraocular pressure is normal doesn’t mean that she doesn’t have glaucoma, so appropriate investigation would definitely involve a good look at the optic nerve and optical coherence tomography of the macular area would be very helpful. 

I’m not sure that I can explain losing cups of tea so I think that it would be a good idea to discuss that with her GP so that can be investigated as well. 

“The missing cups of tea and cyclists in the corner leads me to suspect a homonymous quadrantanopia”

Ceri Smith-Jaynes: Like Kevin, I immediately thought about CBS. I’d ask a bit more about other sensory factors. The images should be silent; if she can hear the cyclists then it is not likely to be CBS. Also, people with CBS usually have good insight – for instance, they can tell that the hallucination isn’t really there.  

There are other conditions and drugs that can cause visual hallucinations, so I would ask if I can write to her GP about it and direct her to the local eye clinic liaison officer and low vision service for support. If the patient is happy using the internet, there’s a useful website, Esme’s Umbrella, that I would direct them to.  

The field loss has many potential causes. Central would imply macular degeneration, whereas a homonymous hemianopia or quadrantanopia would suggest a stroke or tumour beyond the chiasm. The missing cups of tea and cyclists in the corner leads me to suspect a homonymous quadrantanopia. If she is a driver, we may have to talk about field loss and driving.   

Regarding the tea, does ‘misplaced’ mean put it down badly, missing the surface, or simply forgotten where you put it? I have been known to misplace my tea.  

Ankur Trivedi: I agree with all that has been mentioned and agree that, in my limited experience, with this kind of case it does sound like CBS. I would utilise colleagues with more experience with similar cases – those who work with patients within low vision, especially eye clinic liaison officers.    

This is a good example of where optometrists have a part to play in the multidisciplinary team outside of our practice approach, with patients whom we do not always have much exposure to. I have found that CPD and local optical committee events have helped me with this aspect of practice.