Visual Hallucinations

Neurologists and ophthalmologists should be familiar with the causes and treatment of visual hallucinations so that they are able to reassure patients and minimize the anguish associated with untreated visual hallucinations. Hallucinations are under-reported by patients because of the perceived psychiatric implication or because of poor insight into the unreal nature of the hallucinations. In the appropriate setting, physicians should specifically inquire about hallucinations as well as initiate medical treatment. Visual hallucinations have many etiologies and are associated with a variety of disorders. Identification of the associated disorder or cause is necessary to determine the appropriate treatment. Causes and associated disorders include ocular phenomena, migraine, seizures, visual loss (ie, release hallucinations), neurodegenerative disorders, midbrain injury, alcohol and drug effects, narcolepsy, post-traumatic stress disorder, and psychosis. Therapeutic treatment should be directed at the associated disorder or etiology. For instance, antiepileptic drugs may be appropriate for patients with irritative phenomena such as seizures and visual aura of migraine. Depending on the cause, other agents are available and include neuroleptics, cholinesterase inhibitors, and acetazolamide. Well-designed, randomized, controlled clinical trials regarding treatment of visual hallucinations associated with various disorders are lacking. Although complete resolution of visual hallucinations can be difficult, even minimal improvement may be symptomatically beneficial.