Micropsia often occurs as an aura signalling a seizure in patients with medial temporal lobe epilepsy. Most auras last for a very short period, ranging from a few seconds to a few minutes. Drug use
Micropsia can result from the action of mescaline and other hallucinogenic drugs. Although drug-induced changes in perception usually subside as the chemical leaves the body, long-term cocaine use can result in the chronic residual effect of micropsia. Micropsia can be a symptom of Hallucinogen Persisting Perception Disorder, or HPPD, in which a person can experience hallucinogenic flashbacks long after ingesting a hallucinogen. A majority of these flashbacks are visual distortions which include micropsia, and 15-80% of hallucinogen users may experience these flashbacks. Micropsia can also be a rare side effect of zolpidem, a prescription medication used to temporarily treat insomnia. Psychological factors
Psychiatric patients may experience micropsia in an attempt to distance themselves from situations involving conflict. Micropsia may also be a symptom of psychological conditions in which patients visualize people as small objects as a way to control others in response to their insecurities and feelings of weakness. In some adults who experienced loneliness as children, micropsia may arise as a mirror of prior feelings of separation from people and objects. Epstein-Barr virus infection
Micropsia can be caused by swelling of the cornea due to infection by the Epstein-Barr virus (EBV) and can therefore present as an initial symptom of EBV mononucleosis, a disease caused by Epstein-Barr virus infection. Retinal edema
Micropsia can result from retinal edema causing a dislocation of the receptor cells.
Photoreceptor misalignment seems to occur following the surgical re-attachment for macula-off rhegmatogenous retinal detachment. After surgery, patients may experience micropsia as a result of larger photoreceptor separation by edematous fluid. Macular degeneration
Macular degeneration typically produces micropsia due to the swelling or bulging of the macula, an oval-shaped yellow spot near the center of the retina in the human eye. The main factors leading to this disease are age, smoking, heredity, and obesity. Some studies show that consuming spinach or collard greens five times a week cuts the risk of macular degeneration by 43%. Central serous chorioretinopathy
CSCR is a disease in which a serous detachment of the neurosensory retina occurs over an area of leakage from the choriocapillaris through the retinal pigment epithelium (RPE). The most common symptoms that result from the disease are a deterioration of visual acuity and micropsia. Brain lesions
Micropsia is sometimes seen in individuals with brain infarctions. The damaged side of the brain conveys size information that contradicts the size information conveyed by the other side of the brain. This causes a contradiction to arise between the true perception of an objects size and the smaller perception of the object, and micropsic bias ultimately causes the individual to experience micropsia. Lesions affecting other parts of the extracerebral visual pathways can also cause micropsia.