Main genetically-based eye diseases
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Retinal dystrophies These are a series of hereditary retinal diseases that lead to a degeneration of photoreceptor cells (rods and cones). The main one is retinitis pigmentosa, a disease that affects the above-mentioned retinal cells, mainly rod cells, the retinal cells responsible for peripheral vision and vision in low-light conditions. Cones, which are photoreceptor cells in charge of color vision, may also be affected. It is caused by genetic alterations, which may differ between different patients.
- Congenital glaucoma, a rare type of glaucoma affecting newborns and small children, that may be hereditary and has a genetic base.
- Congenital cataract. Cataracts usually appear at advanced ages and consists in the clouding of the crystalline lens. Nevertheless, congenital cataracts are already present at birth due to genetic causes. They are usually hereditary and may affect one or both eyes.
- Inherited strabismus. Eye misalignment may, in some cases, be hereditary. Therefore, in case of family history of strabismus, it is necessary for the child to undergo a comprehensive eye exam.
- Malformations. Anophthalmia (complete absence of one or both eyes), microphthalmia (abnormally small eye globe size) and many other eye malformations.
- Color blindness. Genetically-based alteration associated to X chromosome that affects the ability to perceive colors due to a lack or malfunction of one of the retinal cone cells, responsible to differentiate between green, red, and blue colors.
- Corneal dystrophies, a group of diseases that cause the loss of corneal transparency.
- Atrophy and hereditary optic neuropathies. The atrophy of the optic nerve causes a progressive vision loss due to damages in the optic nerve, and may have a hereditary cause. Another similar disease is Leber Hereditary Optic Neuropathy (LHON), in which mitochondrial inheritance plays an essential role.
- Systemic diseases that affect vision Some systemic diseases with a hereditary basis, such as Graves disease and diabetes, may affect vision.
There are other highly prevalent diseases among general population, such as macular degeneration and glaucoma, that are most likely to affect people having a direct kinship link with other affected people. Age-related macular degeneration is a degenerative disease that affects the central area of the retina, known as macula, which is responsible for central vision. The main risk factor for the disease is advanced age, thus being more likely to be developed from age 60. It causes blurred vision and an alteration in size and shape of images. Glaucoma is a disease that causes damages in the optic nerve, which may lead to a progressive loss of the visual field.