Macropsia is a neurological condition affecting human visual perception, in which objects within an affected section of the visual field appear larger than normal, causing the person to feel smaller than they actually are. Macropsia, along with its opposite condition, micropsia, can be categorized under dysmetropsia. Macropsia is related to other conditions dealing with visual perception, such as aniseikonia and Alice in Wonderland Syndrome (AIWS, also known as Todds syndrome). Macropsia has a wide range of causes, from prescription and illicit drugs, to migraines and (rarely) complex partial epilepsy, and to different retinal conditions, such as epiretinal membrane. Physiologically, retinal macropsia results from the compression of cones in the eye. It is the compression of receptor distribution that results in greater stimulation and thus a larger perceived image of an object. Signs and symptoms
The most obvious symptom of macropsia is the presence of exceptionally enlarged objects throughout the visual field. For example, a young girl might see her sisters books as the same size as her sister. Stemming from this symptom, someone with macropsia may feel undersized in relation to his or her surrounding environment. Patients with macropsia have also noted the cessation of auditory function prior to the onset of visual hallucination, indicating possible seizure either before or after the hallucination. A buzzing sound in the ears has also been reported immediately before macropsia development. Some patients claim that symptoms may be eased if an attempt is made to physically touch the object which appears enormous in size.
Computer software, such as the Aniseikonia Inspector, has been developed to determine the prescription needed to correct for a certain degree of aniseikonia. The problem with correction through optical means is that the optics do not vary with field angle and thus cannot compensate for non-uniform macropsia. Patients have reported significantly improved visual comfort associated with a correction of 5-10% of the aniseikonia.With regard to drug-induced or virus-induced macropsia, once the underlying problem, either drug abuse or viral infection, is treated, the induced macropsia ceases. Research
Future research may focus on ways to limit the occurrence of retinally-induced macropsia due to surgery. In terms of treatment, the most effective optical correction is still being researched with respect to visual field angles and direction to a target. The susceptibility of certain age demographics to macropsia is a subject that requires further validation. Overall, there have not been very many reports of macropsia induced by certain drugs, specifically zolpidem and citalopram. Once a larger effort is made to compile such reports, there will inevitably be more research on the subject of macropsia. References


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