SENSORY IMPAIRMENTS
Sensory
impairments consist of hearing and visual impairments
Visual Impairment Mild visual impairments with low vision, includes totally blind
Prevalence:
-in children, blindness is the least prevalent
of all disabilities
-about 1/1000 children under 18 yrs. of age have
severe vision impairment
-vision loss is primarily an adult disability
-only 10-15% of total population are totally
blind
Etiology
Category
|
Example
|
Manifestation
|
Etiology
|
Refractive
Errors
|
Myopia
Hyperopia
Astigmatism
Cataracts
|
Nearsightedness
Farsightedness
Distorted or
blurred vision
Growth over
lens
|
Aging,
heredity, disease, and infection
|
Eye
pathologies
|
Glaucoma
Retinopathy of
prematurity
Retinoblastoma
Albinism
Optic nerve
atrophy
Retinitis
pigmentosa
|
Impaired
outflow of vitreous fluid causes pressure on eyeball
Fibrous mass
that destroys the retina
Malignant
tumour on the retina
Lack of skin
pigmentation
Nerve
degeneration
Narrowing of
field
|
Congenital,
hereditary
Prematurity;
oxygen in incubator
Genetic
Genetic, error
of metabolism
Damage to the
optic nerve
Hereditary of
vision
|
Oculomotor
problems
|
Strabismus
Nystagmus
Amblyopia
|
Seeing double
Rapidly moving
eyeballs
Lazy-eye
blindness; lack of depth perception
|
Arises from
strabismus
|
Other problems
|
Colour
blindness
Photophobia
|
Deficient in
colour vision
Sensitivity to
light
|
Genetic
|
Syndromes
|
Usher’s
syndrome
Joubert
syndrome
|
Retinitis
pigmentosa and progressive hearing loss
Ataxia, slow
motor activity, nystagmus
|
Genetic
Neurological
disorder
|
I thought that glaucoma was something that developed with age, and is hereditary. How many children of school age have glaucoma and is there another etiology (i.e environmental)?
ReplyDeleteFrom the Ontario Association of Optometrists:
ReplyDeleteGlaucoma is an eye disease that affects nearly one percent of the people in Canada. Initially, glaucoma causes peripheral vision loss. If left untreated, it can lead to a complete loss of vision. Glaucoma is a very serious disease but with routine eye exams and early detection, the visual damage can be minimized.
The cause of glaucoma is not fully understood, but the belief is that there is an increase of pressure inside the eye. Aqueous humour is a fluid which is produced inside the eye. If there is too much production or not enough drainage of the aqueous humour, the pressure inside the eye will increase. This increase in pressure compresses the optic nerve which is responsible for relying visual information to the brain. The tiny nerve fibers that make up the optic nerve are destroyed. Glaucoma can also occur without a significant increase in eye pressure. This is referred to as low tension glaucoma. The belief in low tension glaucoma is that there is poor blood flow to the optic nerve despite a normal eye pressure.
Once again, damage to the nerve fibers occurs.
Who is at risk for developing glaucoma? The number one risk factor is increased eye pressure. The health of the optic nerve is also very important. Any family history of glaucoma can increase chances of developing the disease. Race also plays a role as African Americans are at greatest risk, followed by Hispanics and then Caucasians.
Unfortunately there are very few symptoms associated with glaucoma. Some patients may notice mild vision loss if any at all. Early signs of glaucoma can be detected by your optometrist or ophthalmologist by testing your peripheral vision. This is essential to diagnose glaucoma since it affects peripheral vision first. One type of glaucoma is closed-angle glaucoma. Symptoms will include sudden blurred vision, headaches, nausea, vomiting and severe pain around the eye. Another type is infantile glaucoma which will cause a baby to constantly rub their eyes. The baby will take on a cloudy appearance to their eyes and will also be light sensitive.
How is glaucoma treated? The goal of glaucoma treatment is to lower the eye pressure even in cases of low-tension glaucoma. This is accomplished with several types of pressure-lowering eye drops. Occasionally laser treatment or surgery has to be considered if the drops prove to be ineffective.
It is standard practice for optometrists and ophthalmologists to screen all patients over the age of nineteen for glaucoma. During routine eye examinations we check for glaucoma by measuring eye pressures and assessing both optic nerves. It is advisable for all adults to have an eye exam every one to two years to properly screen for glaucoma and other eye diseases.