Macropsia

Synonyms

Megalopsia; Megalopia

Definition

Macropsia is a condition in which visual objects are perceived to be larger than actual size. Surrounded by seemingly enlarged objects, the individual with macropsia may have a corresponding experience of being smaller than actual size. Macropsia can arise from disorders throughout the visual system including peripheral visual organs or visual components of the central nervous system. Macropsia can be a clinical feature of migraine, stroke, viral disease, or epilepsy; it can also be associated with prescription or illicit drug use or recently prescribed presbyopic correction.

At the physiological level, macropsia can occur when retinal rod and cone cells become more tightly arrayed, for example, in a setting of macular scarring or tumor. With increased density of photoreceptors, the retinal representation of an observed object causes it to be perceived as enlarged. Macropsia is also thought to occur as a result of impairment of ocular...