Micropsia is a change in visual perception caused by swelling in the corneal areas of the eye. In general, those with micropsia perceive objects as much smaller than their actual size. The condition has also been called Alice In Wonderland Syndrome, and the effect is sometimes given the fanciful name of Lilliput sight after the novel Gulliver's Travels.
Micropsia is usually a temporary condition that can be caused by several factors. Some types of epilepsy have been known to cause visual distortion. The onset of migraine headaches may be marked by micropsia. In addition, swelling caused by the Epstein-Barr virus has been linked to episodes of micropsia.
Children between the ages of five and ten seem particularly prone to micropsia, as well as macropsia, which causes things to appear bigger than they are. These symptoms, which can prove extremely distressing, may lead to panic or severe disturbance in young children. They are almost always associated with conditions that can lead to migraine headaches at a future point. Such perceptions should be taken seriously, however; in vary rare cases, swelling of the brain or tumors may cause perceptional differences.
Micropsia is a fairly common symptom of the use of both hallucinogenic and opiate-based drugs like hydrocodone and oxycodone. Morphine and heroin in particular are associated with this condition, and may also cause other difficulties perceiving spatial relationships. Such differences can heighten the panic of drug users or of those hospitalized. A calm explanation of this condition is often helpful to those on high doses of pain medication, so such symptoms are not completely unexpected.
In rare cases, micropsia can be of psychological origin. Someone with extreme anorexia might be able to look at a friend and see a perfect figure, but be unable to see such a figure in herself. Visual perceptions affecting body perception are often labeled as body dysmorphic disorder.
There are few studies on how to prevent micropsia in those who seem predisposed due to medical reasons. When illness or migraines cause the condition, it is usually short-lived and is not treated. Control of migraines through medication may cause micropsia to be of shorter duration. Knowledge that the condition may occur seems to be most helpful in easing panic related to extreme difference in perception.
In the case of Epstein Barr Virus leading to mononucleosis, micropsia may present as an initial symptom. This symptom may provide a reason to test for mononucleosis, but usually no specific treatment for the micropsia itself is undertaken. Usually, the condition improves within a few days.