Eyes | Ophthalmology | Vision Loss (Symptom)
Vision loss/blindness is the absence of vision due to damage to the transparent media of the eye, the retina, and the nerve centers. Vision loss may be partial or total, acquired or congenital. In case of partial blindness: the best eye acuity is between 1/20 and 1/50 to almost total blindness: the best eye acuity is between 1/50 and the threshold of perception of light when it is complete: the light is not perceived. People who see less than 20/200 are considered blind.
Diabetes is the leading cause of blindness in adults aged between 20 and 74. Retina is a thin membrane located at the back of the eye. It consists of cells that provide the visual image and send it to the brain. Retinal diseases, including macular degeneration, diabetic retinopathy and retinal detachment may cause vision loss. Worldwide, the leading causes of blindness are: cataract, leprosy, deficiency of vitamin A, trachoma. Loss of central vision causes may include: darkening the visual field; cataract; macular degeneration; optic neuritis - may cause sudden loss, unilateral central vision; multiple sclerosis - can cause optic neuritis; brain tumours; brain aneurysm. Peripheral vision loss causes are: darkening the visual field; retinal detachment.
Other causes may include: damage to the eye; glaucoma; certain eye diseases; stroke; multiple sclerosis; optic nerve compression; intracranial hypertension; bilateral papilledema; bilateral cerebral infarction in the occipital lobe; blockage of blood vessels; complications of premature birth; complications from eye surgery; amblyopia; optic neuritis; retinoblastoma; poisoning; optic glioma (glioma or optic pathway).
Having a predisposition to blindness increases the risk of acquiring it, but does not always lead to blindness. Conversely, the absence of risk factors or eye protection does not guarantee that a person will not suffer from blindness. Sudden loss of vision will always be considered an emergency, even if it does not affect the patient completely. ...