Here you will find a list of the major medical
and non-medical causes of blindness in children and adults
Medical causes of Blindness:
1. Infections of the mother. e.g.. German measles of pregnant lady leads to
birth of a baby with cataract -------> blindness if not treated early.
2. Trachoma: it causes bilateral keratoconjunctivitis in childhood which results in
corneal scarring in adulthood. This
results in blindness if severe.
3. Xerophthalmia: due to hypovetaminosis A. It is a common cause of
blindness especially in infants.
4. Glaucoma. : It is an increase in intraocular pressure causing damage
to the optic nerve. A patient with glaucoma loses peripheral
field of vision, but central vision is maintained.
5. Retinal detachment.
6. Diabetic Retinopathy: Diabetes causes visual loss in the elderly.
It affects the lens and causes cataract. It also involves the retina
. It is associated with new blood vessel formation.
7. Heredity: e.g. Congenital Glaucoma & Retinoblastoma.
8. Degenerative Retinal Disorders, glaucoma, diabetes: Blindness in elderly
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9. Cataract: Major cause of blindness (about 50% of blindness worldwide).
Cataract due to dehydration, UV light, congenital.
10. Sudden loss of vision: these all relate to blood supply of the eye
a. trauma: to the occipital, but vision returns in hours.
b. migraine: distorted or blurred vision characterized by flashing
lights. In addition loss of vision can be complete and it
returns in minutes.
c. Arterial hypo tension: it can be accompanied by temporary
loss of vision.
d. Increased intracranial pressure.
e. Metabolic disorders: e.g.. hypoglycemia.
f. Cerebral venous sinus thrombosis.
g. Thrombosis in the central vein of the retina or in the central
retinal artery.
h. Cranial arteritis may cause blindness
i. Exogenous drugs and toxins. e.g. lead poisoning and
chloramphenicol toxicity.
j. Hysterical Blindness: visual loss characterized by tunnel
vision. Complete blindness is less common.
11. Congenital malformations:
a. retinal aplasia: pupilary responses are absent.
b. congenital optic atrophy: signs of this disorder which is
inherited as an autosomal recessive trait are obvious at birth or shortly
thereafter.
c. congenital hydrocephalus.
d. Hydranencephaly: failure of development and blindness become
evident over the first few months of life.
12. Prenatal Anoxia or Hypoxia.
13. Congenital infections: the TORCH complex of infections may produce blindness present at birth or evidence of visual loss
later in life.
14. Congenital cataracts: cataracts can be extensive enough to
interfere with vision.
15. Optic atrophy: which can be a result of various disorders both congenital
and acquired.
a. traumatic causes: e.g.. chronic subdural hematoma.
b. degenerative disorders: e.g.. Tay-Sachs Disease of which
symptoms begin in the first months of life with hyperacusis and
irritability. Delayed motor development and
decreased visual acuity become apparent by 6 months of life.
c. neoplastic lesions either optic or in other brain parts
resulting in visual defects according to their locations.
d. vascular lesions: unilateral blindness may result from
compression of the optic nerve by an intracranial aneurysm.
e. bony overgrowth: e.g.. osteoporosis. In this disorder
generalized sclerosis of the bone decrease the size of the cranial
nerve foramina resulting in nerve compression and
thus blindness occurs.
16. Retrolental fibroplasia: varying degrees of retinal scarring and visual
loss may be found. Infants at risk should be observed
carefully for early signs. It is an
extensive growth of blood vessels on the retina. The growth usually occurs
between 4
weeks and 14 weeks of life and can lead to
retinal scarring, detachment and blindness.
17. Retinitis Pigmentosa: this condition is characterized by progressive
disorganization of the pigment of the retina usually
accompanied by a decrease in the number of
retinal vessels and some degree of optic atrophy.
18 Miscellaneous causes:
a. retinoblastoma
b. retinal detachment
c. drugs and toxins: of these which may impair vision are methanol,
streptomycin, quinine, isoniazid, thallium, arsenic and
penicillamine.
19. Macular degeneration: familial degeneration of the maculae and it is the
commonest cause of blindness in older life. In its
early stages new blood vessels grow between
the choroid and the retina producing minor retinal detachment. In
this
disorder loss of central vision
begins at second decade. Peripheral vision is maintained for
years before total blindness
occurs.
20. Toxocara infestation.
21. Cataracts: clouding of the lens of the eyes resulting in decreased
vision. Cataract can be congenital (in case of maternal
infection with rubella virus or inherited
as an autosomal dominant trait or in case of being a result of other systemic
disorders such as galactosemia) or acquired in
case of diabetes.
22. Onchocerciasis (river blindness): transmitted by bite of black fly
Non-medical causes:
1. Drugs and toxins: e.g.. drugs with an atropine like action such as
antidepressants, tranquillizers and anti-Parkinsonian drugs.
These cause blurring vision and aggravate glaucoma.
Steroids may predispose to cataract.
Chloroquine used to treat rheumatiod arthritis and ehtambutol used
to treat tuberculosis may damage the retina.
2. Trauma: common cause of unilateral blindness in children and young adults.
Young adults especially men are the most likely
victims of penetrating ocular injuries. Domestic
accidents, exploding batteries, sports related injuries and motor vehicle
injuries.
3. UV Radiation.
4. Emotional state.
5. Occupational circumstances:
a. grinding and grilling may propel tiny fragments of metal, stone,
wood or glass into the surrounding environment at high
speeds resulting in their entrance into the
eye through the cornea or sclera.
b. tools with sharp ends used without caution.
c. welding arcs producing ultra violet radiation that may cause
blindness.
e. industrial chemicals especially those associated with acids and
alkalis
6. Chemicals used at homes or as pesticides.
