Myopia is often called near-sightedness and usually results when the eye is larger than normal. It is the most common eye disease in the world affecting perhaps 25% of the population. It is often present as part of a syndrome caused by gene mutations but it may also be an isolated finding. Little is known about the cause of myopia but it is generally considered to be the result of many factors, both environmental and genetic, that impact the growth of the eye.
Most near-sightedness is mild with few consequences other than blurry vision which can be corrected with glasses. However, a small percentage of myopes have so-called high myopia or extreme near-sightedness which raises the risk of retinal degeneration or detachments. It may also lead to early cataracts and degeneration of the macula which is a highly specialized area of the retina that we use for our sharpest vision.
Children are reported to have poor vision at a young age but it is unknown if it is congenital. The eye is abnormally elongated leading to severe near-sightedness. Visually significant cataracts (opacities in the lens) requiring surgery are found in the majority of patients during the first or second decades of life. The lenses are sometimes dislocated as well. Portions of the retina (light-sensing tissue in the back of the eye) develop degenerative changes increasing the risk of retinal detachments.
There are usually no changes in other parts of the body although one patient was reported to be deaf.
This is an autosomal recessive condition in which both copies of a gene are changed (mutated). Parents who are carriers of a single mutated copy do not have the eye disease. Two such parents, however, can expect that each of their children has a 25% risk of developing this disorder.
This condition is diagnosed and treated by an eye doctor since there are no abnormalities outside of the eye. Visually significant lens opacities (cataracts) can be surgically removed but considerable skill is required and complications pose a considerable risk because of the instability of the lenses. Retinal detachment surgery should be attempted since without it blindness is inevitable. However the nature of the detachment and the degeneration of the retina makes repair difficult and blindness may result.
Outside of the visual difficulties, patients live a comfortable live and lifespan is not impacted.