Optic nerve hypoplasia 928781 222785932 2008-07-01T02:50:04Z 72.220.41.6 /* Cause */ associating marijuana with optic nerve hypoplasia {{DiseaseDisorder infobox | Name = Optic nerve hypoplasia | ICD10 = Q07.81 | ICD9 = {{ICD9|743.57}}-{{ICD9|743.58}} | }} '''Optic nerve hypoplasia''' is a medical condition that results in underdevelopment of the [[optic nerve]]s. ==Development of the optic nerve== During the second month of pregnancy, a structure called the optic stalk develops into a pair of optic nerve bundles. These bundles send signals from the eyes to the [[occipital lobe]] of the brain, naturally undergo pruning as the [[fetus]] develops. In some individuals, however, either this pruning process is too complete, or the nerves simply fail to develop fully. Such an occurrence causes a congenital condition called optic nerve hypoplasia (ONH). ==Symptoms== Optic nerve hypoplasia can appear in one or both eyes, causing anywhere from a mild to serious visual impairment in the form of decreased [[visual acuity]] and [[visual field]]s. People with this condition are also more likely to present with [[photophobia]] and [[nystagmus]]. Because optic nerve hypoplasia involves the underdevelopment of structures located within the brain, the condition may also be found in conjunction with a constellation of hormonal imbalances and midline brain defects known as [[septo-optic dysplasia]]. ==Cause== No one is certain as to what causes optic nerve hypoplasia. The condition is usually not hereditary, but it occurs relatively often in people with [[albinism]], which is hereditary. There is but a weak correlation between young maternal age, or maternal diabetes, and the occurrence of this condition. It cannot be tied in with any harmful maternal activities, but there is one study<ref>Strömland, K., & Pinazo-Durán, M.D. (2002). Ophthalmic involvement in the Fetal Alcohol Syndrome: Clinical and animal model studies. ''Alcohol and Alcoholism'', ''37(1)'', 2-8.</ref> that suggests children with [[Fetal alcohol syndrome]], or prenatal alcohol exposure, often have optic nerve hypoplasia. It has also been related to marijuana use by pregnant mothers. Recent studies have found a correlation between the optic nerve and THC. Medicinal marijuana use has most commonly been associated with glaucoma, to relieve pressure on the eyes. THC has been found to interact with a baby's eyes in the womb, thus retarding the growth of the optic nerve. ==Prognosis== The visual prognosis in optic nerve hypoplasia is quite variable. Occasionally, optic nerve hypoplasia may be compatible with near-normal vision; in other cases, one or both eyes may be functionally, or legally [[Blindness|blind]]. Although most patients with optic nerve hypoplasia lead normally productive lives, those with septo-optic dysplasia may experience non-visual problems, for example, with growth retardation. ==References== {{reflist|2}} ==External links== *[http://www.blindbabies.org/factsheet_onh.htm Optic Nerve Hypoplasia Facts] *[http://www.tsbvi.edu/Outreach/seehear/spring99/opticnerve.htm More Optic Nerve Hypoplasia Facts] *[http://www.magicfoundation.org/www/docs/101.116/optic-nerve-hypoplasia.html Optic Nerve Hypoplasia Information and Network support The MAGIC Foundation] *[http://www.focusfamilies.org/focus/usdefault.asp FOCUS Families] - information, education, and support. [[Category:Blindness]] [[Category:Ophthalmology]] [[Category:Neurology]] {{eye-stub}}