Visual hallucinations during visual recovery after central retinal artery occlusion

Background: Charles Bonnet syndrome is characterized by complex, formed visual hallucinations that occur in patients without psychiatric disorders. To the best of our knowledge, it has not been described following central retinal artery occlusion. Objective: To describe 2 patients who experienced formed visual hallucinations characteristic of Charles Bonnet syndrome after sudden, severe visual loss precipitated by central retinal artery occlusion. Patients: Two patients, aged 77 and 63 years respectively, experienced sudden deterioration of vision following central retinal artery occlusion. Formed visual hallucinations occurred in patient 1 six days later and in patient 2 two days later. Results: The hallucinations appeared both within and at the borders of the patients' residual intact visual fields. They occurred during periods when the patients experienced partial visual recovery associated with enlargement of their visual fields. The visual recovery and hallucinations both ceased at the same time. Conclusions: We propose that the hallucinations are likely the result of deafferentation and their occurrence during visual recovery suggests that they are a correlate of visual system plasticity.