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Unit 8: Identification, Causes, Problems of Visually Impaired

(v) Early intervention for students with visual impairment is .............in enhancing social, physical Notes
and intellectual development.

8.2 Causes of Blindness, Impaired, Low Vision, Vision Loss, Legally
Blind, Loss of Vision

Blindness is frankly lack of vision. Only those who experience no light perception are considered
totally blind. And few are totally without some glimmer. Legally blind refers to vision less than 20/
200 or peripheral (side) vision is 20 degrees or below.
(i) Visually impaired refers to a loss of vision that is uncorrectable or not correctable to a normal
level. Vision impairment may be caused by:
• loss of visual acuity ~ objects unclear
• incorrect eye shape ~ harder to focus on stuff
• brain doesn't process visual information correctly
• damage to the eye ~ affects ability to receive or process visual information
• loss of visual field ~ cannot see wide area without moving eyes or turning head
(ii) Typical causes for blindness or loss of vision globally include:
• lazy eye • sports injury
• stroke or TIAs • chemical burns
• endophthalmitis • vitamin A deficiency
• blocked blood vessels • eye surgery complications
• cataracts ~ eye lens cloding • glaucoma ~ optic nerve damage
• retinoblastoma ~ form of eye cancer • trachoma ~ type of Chlamydia infection
• optic neuritis ~ optic nerve inflammation • optic glioma ~ slow growing benign tumors
• diabetic retinopathy ~ complication of diabetes
• retinitis pigmentosa ~ progressive retinal damage
(iii) A couple of these losses cause only temporary blindness.
Your vision loss may only involve part of the visual field, known as visual field defects. For
instance:
• diabetic retinopathy, hypertensive retinopathy, retinal detachment ~ causes small, irregular
vision patches
• tumor, aneurysm near pituitary gland ~ causes inability to see the outside part of the visual
field in either eye
• macular degeneration, certain optic nerve damage ~ causes loss of ability to see things in the
center visual field
• stroke, tumor affecting brain's left side ~ causes inability to see all or part of visual field on
right side for both eyes
• glaucoma, certain retinal disorders (i.e. retinitis pigmentosa) ~ causes vision loss in all
directions.

What is recent position of blind children in India?

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