1. Genetic Causes
Genetic causes of blindness can include inherited disorders such as retinitis pigmentosa, congenital cataracts, and macular degeneration. These conditions are caused by genetic mutations that affect the structure or function of the eyes.
2. Medical Conditions
Medical conditions such as glaucoma, diabetic retinopathy, and age-related macular degeneration can lead to vision loss. Glaucoma is caused by increased pressure in the eye, while diabetic retinopathy is caused by damage to the blood vessels in the retina. Age-related macular degeneration is caused by deterioration of the macula, a small area in the center of the retina.
3. Eye Injuries
Eye injuries such as blunt trauma, chemical burns, and penetrating injuries can cause blindness. Blunt trauma can cause retinal detachment, while chemical burns can cause corneal scarring. Penetrating injuries can cause retinal damage or loss of vision.
4. Infections
Infections such as trachoma, toxoplasmosis, and herpes simplex can cause blindness. Trachoma is a bacterial infection that can cause scarring of the cornea, while toxoplasmosis is a parasitic infection that can cause retinal damage. Herpes simplex can cause inflammation of the cornea.
5. Nutritional Deficiencies
Nutritional deficiencies such as vitamin A deficiency can cause blindness. Vitamin A is important for the development and maintenance of healthy eyes, and a deficiency can lead to night blindness and corneal ulceration.
6. Toxic Substances
Exposure to toxic substances such as lead, arsenic, and mercury can cause blindness. Lead can affect the optic nerve, arsenic can cause retinal damage, and mercury can cause corneal damage.
7. Diseases of the Brain and Nervous System
Diseases of the brain and nervous system such as stroke and multiple sclerosis can cause blindness. A stroke can cause damage to the optic nerve, while multiple sclerosis can cause optic neuritis.