Legally Blind-20/200 or less in better eye/narrow field less than 20◌. LOW vision- not so severe (can read larger print).
Aqueous humour- watery substance between cornea&lens. 1/10 children&adults blind. Visual ability common measured w/
Snellen chart (usually at 20ft dist). Causes:most com- REFRACTION (bent light rays).Myopia = nearsighted (when eyeball is
too long) Hyperopia=farsighted (eyeball is too short)Astigmatism- blurred vision(irregular cornea/ lens formation)
Glaucoma= often due to pressure in the eyeball &cause is UNKNOWN.(untreated,blindness occurs) Cataracts= caused by
clouding of lens of eye-affects colour&distance. Diabetic retinopathy =results from interference withblood supply levels to
retina.RetinitisPigmentosa= hereditary resulting in degeneration of retina& can start in infancy/earlychild/ teen years. Also
affects ability to see in low light(night blindness)and causes field of vision to narrow. TunnelVision= problems in peripheral,
or narrowing ofFOV*Several other visual impairments primarily affect children.Visual impairments of school-age children are
often due to prenatal causes,many are heredity.IntellectualAbility-NO reason believe blindness leads toˇintelligence.Ind.w/
blindness 'see w/ their fingers'.CognitiveMapping- way of conceptualizing the spacial environ( allows better mobility)
ObstacleSense =skill-can detect presence of obstacles.(NOT indicator of extra sense,but to detect changes in ECHOES).
Doppler effect- describe pitch of a sound rises as person moves closer towards source.Louis Braille (blind,created).
problem-some become dependent on large-print books;disadvantage when encounter situations,(jobs) where large-print is
NOT available. ASDAPPARENT before age 3. Aspergers-mild autism w/out signif. impairments (lang/cog) – problems in
social situations. PERVASIVE DEVELOP.DISORDERS-->autism (impaired cog.),apergers(mild aut.No delay in lang.Average
-above av.Intel).,rett(after norm.Devel.Head growth slows,loss of hand skill & soc,engagement.Moreprev. in females),child
disintegrative disorder(norm.Dev.Then loss of skills in at least [2]:lang,social skills,bladder control,play,motor skills.More
prev.In males). 4 most common symptoms of what brain injury entails for children: 1) Injury to brain by external force
2)injury not caused by degenerative/congenital condition 3) Diminished/altered state of consciousness 4) Neurological/
neurobehavior dys. Majority who aredeaf-blind have someother exceptionality-about11%ndividuals between birth-22
have intellectual disability**over50GENETIC CHROMOSOMAL syndromes associatedw/ deaf blindness. Acute-> w/
time/treatment,person will recover (ex:car accident)• Chronic-constantly ongoing,does not go away(cerebralpalsy)
Episodic;reoccur,most of time individual can function normally.Episodes don't become more severe -( ex:Asthma and
seizure disorders> c
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