CAUSES OF LOW VISION Flashcards
Common causes of low vision
Cataracts
Albinism
Diabetic Retinopathy
Corneal scarring
HIV related dse.
Optic nerve head dse.
Trauma
Retinitis pigmentosa
Glaucoma
Microphthalmos
Macular degeneration
Cortical blidness
Aniridia
Symptoms of low vision
Distorted VA, near and distance
Restricted visual fields
Deprived night vision
Defected color vision
Severely reduced contrast sensitivity
Difficulty performing activties
Differing light levels needed
Need more time to do activties
Become tired more quickly
Categories of low vision
Reduced VA
Reduced CS
Reduced VF
One of the most common symptoms of eye dse. Causing low vision
Reduced VA
Reduced VA may occur as a result of
Cataracts
Keratoconus
Microcornea
Corneal degeneration
Failed corneal graft
Dislocated lens
Aniridia
Albinism
Effect of overall reduced VA
Reduce quality of life of persons
Affects everyday activities like reading, writing, driving
Behavioral manifestations of reduced distance VA
Difficulty in…
Recognizing details
Learning by imitation
Orientation and mobility
Reading road signs
Driving
Behavioural manifestations as a result of a secondary reduction in contrast sensitivity
Bumping into objects like door frames or furniture
Seeing time on a watch can be difficult
Identifying coins and currency may be problematic
Difficulty in walking down steps
Difficulty in driving and mobility in a dimly lit area
Difficulty in reading poor contrast materials like the newspaper
Management of reduced VA
Spectacles
Telescopes for distance viewing
Magnifiers
LVAs supplemented with environmental modifications and the use of color to enhance the effects of dse. Conditions
May occur early in disease condition when VA may not be or minimally affected
Reduced CS
T/F
Very often patients having reduced contrast sensitivity also very sensitive to lighting and glare
T
Management of reduced contrast sensitivity
Filters
Environmental modifications to enhance contrast either by adding color contrast
Lighting modifications to avoid glare
Closed-circuit televisions
Ocular conditions resulting in central field loss:
ARMD
Best’s dse.
Stargardt’s macular dystrophy
Macular hole
Macular coloboma
Myopic degeneration
Chorioretinitis
Produces inability to perceive objects or people in direct line of sight
Central visual field loss
Type of central VF where the center is only blurry
Central relative scotoma
Type of central VF where the center is complete dark
Central absolute scotoma
Behavioural manifestations that may occur as a result of central field loss
• Not talking directly to people
• Unusual head position
• Lack of eye contact
• Diminishing ability to recognize people in front of them
• The secondary reduction in VA may produce difficulties in reading and writing
Behavioral manifestation of poor color vision
• Inability to identify colour of objects
• Uncoordinated clothing
• Sorting fruits and vegetables difficult
• Issues identifying medicines
• Identifying food on plate difficult
Management for central VF
Training eccentric viewing
Low powered magnifiers
Fresnel prisms
Line guides
Affects the individual’s ability to perceive people or objects to the sides
Peripheral field loss
Vision is partially obstructed or non-existent in the affected field
Peripheral field loss
Ocular conditions producing peripheral field loss
Retinitis pigmentosa
Glaucoma
Leber’s congenital amaurosis
Optic atrophy
Lasered diabetic retinopathy
ROP
Retinal detachment
Multiple sclerosis
Behavioral manifestations in response to peripheral field loss
Unusual head movements
Difficulty in reading
Uncertainty in mobility
Inability to find lost objects
Behavioral manifestation in partial blurred vision
Difficulty in reading and writing
Difficulty in recognizing details
Difficulty in reading road signs
Difficulty in orientation and mobility
Management of peripheral field loss
Orientation and mobility
Reverse telescopes
Minus lenses
Fresnel prisms
Mirrors