macropsia

   Also known as macropsy, macroptic vision, megalopsia, and megalopia. The term macropsia comes from the Greek words makros (large) and opsis (seeing). It refers to a visual distortion in which objects and stimuli are perceived as disproportionally large. The process ofincreas-ing the apparent size of objects and stimuli is called "magnification. When macropsia sets in gradually rather than abruptly, it is called " zoom vision. When objects are repeatedly magnified and minified in the course of seconds, the term " pulsation phenomenon applies. Macropsia is classified either as a type of "dysmetropsia or as a " metamorphopsia. It can occur physiologically in the form of " oculomotor macropsia, but it can also occur in the context of neurological disease. In the context of disease, macropsia may present as an isolated symptom, as part of an "aura, or as part of a cluster of symptoms called the " Alice in Wonderland syndrome. Etiologically, macropsia is associated primarily with paroxysmal neurological disorders such as epilepsy and migraine. It can also be evoked by intoxication with alcohol or with "hallucinogens such as LSD and mescaline. In " hemimacropsia, the perceived enlargement of objects restricts themselves to one of the visual hemifields. The term "central macropsia is used to denote a type of macrop-sia that restricts itself to the central field of vision, leaving objects and stimuli perceived in the periphery of the visual field in their normal proportions. The term macropsia is used in opposition to " micropsia. It should not be confused with the term " macroptic hallucination. Conceptually, macropsia can be considered the visual equivalent of "macrostereognosia (i.e. feeling things as larger than they are). The two conditions have also been known to occur in conjunction.

   References

   Critchley, M. (1949). Metamorphopsia of central origin. Transactions ofthe Ophthalmologic Society of the UK, 69, 111-121.

   Park, M.-G., Choi, K.-D., Kim, J.S., Park, K.-P., Kim, D.-S., Kim, H.-J., Jung, S. (2007). Hemi-macropsia after medial temporo-occipital infarction. Journal ofNeurology, Neurosurgery and Psychiatry, 78, 546-548.