Eyes | Ophthalmology | Blindness (Symptom)


Blindness is the condition of lacking visual perception due to physiological or neurological factors, the inability to see. In a strict sense the word blindness denotes the condition of total blackness of vision with the inability of a person to distinguish darkness from bright light in either eye.


Blindness may result from injury to, disease or degeneration of, the eyeball; the optic nerve or nerve pathways connecting the eye to the brain; or the brain itself. Uveitis and cataract are other common causes of blindness. Clouding of the cornea may result from Sjögren’s syndrome, vitamin A deficiency, chemical damage, infections, and injury. Corneal ulcer can cause blindness due to scarring of the cornea. Diabetes mellitus, hypertension, or injury cans all cause bleeding into the cavity of the eyeball and subsequent loss of vision. Bleeding into the fluid in front of the lens hyphenates or behind the lens vitreous hemorrhage can also result in loss of vision.

Other conditions that may cause blindness include glaucoma; retinal artery occlusion or retinal vein occlusion; age-related macular degeneration; retinopathy; retinal detachment; tumors such as retinoblastoma and malignant melanoma, juvenile of the eye; and retinal hemorrhage. Blindness can occur in combination with such conditions as mental retardation, autism spectrum disorders, cerebral palsy, hearing impairments, and epilepsy. People with albinism often have vision loss to the extent that many are legally blind, though few of them actually cannot see.

Diagnosis and Treatment

Blindness is diagnosed by visual acuity testing in each eye individually and by measuring the visual field or peripheral vision. Patients may have unilateral blindness (in one eye) or bilateral blindness (both eyes). Historical information regarding the blindness can be helpful in diagnosing the cause of blindness.

Treatment depends on the underlying cause. If the loss of vision cannot be corrected, the patient may then be registered as legally blind or partially sighted.