Intro to low vision Flashcards
What is the WHO definition of vision impairment?
“A person with low vision is one who has impairment of visual functioning even after treatment and/or standard refractive correction, and has a visual acuity of less than 6/18 to light perception, or a visual field of less than 10 degrees from the point of fixation, but who uses, or is potentially able to use, vision for planning and/or execution of a task.”
What is the WHO definition of low vision?
VA less than 6/18 but equal to or better than 3/60 in the better eye with best correction
(ICD 10, 1&2)
What is the WHO definition of blindness?
VA less than 3/60 or visual field loss of less than 10 degrees in the better eye with best correction
(ICD 10, 3,4 & 5)
What are the global top causes of VI?
Uncorrected RE
Cataracts
AMD
What are the global top causes of blindness?
Cataract
Uncorrected RE
Glaucoma
In the UK, what percentage of those registered sight impaired are over 65?
80%
What is the UK definition of severely sight impaired?
“So blind as to be unable to perform any work for which eyesight is essential”
VA <3/60 with full visual field.
VA >3/60 and <6/60 with significantly contracted field of vision (doesn’t include longstanding vision defect with no VF defect).
VA >6/60 with severely contracted visual field, especially in lower field (not homonymous or bitemporal hemianopia if VA >6/18).
What is the UK definition of sight impaired?
“Substantially and permanently handicapped by defective vision caused by congenital defect, illness or injury.”
3/60 to 6/60 with full field.
Up to 6/24 with moderate field restriction, opacities or aphasia.
6/18 or better with gross field defect.
What are some negatives of the VI definitions?
Near VA and CS aren’t considered.
All use best corrected VA (underestimates prevalence)
What are the parts of vision impairment certification?
- Consent and category o registration
2a. Px info
2b. VA, VF, effect of glare
2c. Diagnosis - Other relevant info
What is the most common cause of VI?
Macular Degeneration
What are some later life causes of VI?
Optic atrophy
Cataract
AMD
Hypertensive retinopathy
Glaucoma
What are some mid life causes of VI?
Retinitis Pigmentosa
Myopic degeneration
Glaucoma
Corneal causes
Trauma
Retinal detachment
MS
Diabetic retinopathy
What is the most common cause of VI in kids?
Cerebral/visual pathway issues
What are the functional effects of VI?
Significant restriction or difficulty with everyday activities
Reduced QoL
Depression
What are the limitations for AMD?
Difficulty reading
Poor face recognition
Unable to drive
Difficulty entering areas of low luminance
What advice should you give someone with AMD?
They will only lose their central vision (won’t go completely blind).
Visual hallucinations are common.
Keep lighting at home even, with no dark spots.
What are the limitations of glaucoma?
Constricted VF
Orientation
Mobility
Unable to drive
What are the limitations of cataract?
Night driving difficult
If advanced, unable to drive
Disability glare
Difficulty reading print with poor contrast
Poor VA
Mobility
Altered colour perception (could cause problems choosing clothes)
What are the limitations of diabetic eye disease?
Reduced VA and CS (difficulty reading)
Changes to dark adaptation
Patchy VF loss
Poor facial recognition
Unable to drive
Changes to colour vision (could cause problems choosing clothes)
What are the limitations of albinism?
Variable vision if tired
Nystagmus may cause postural difficulties
Accommodation problems
Photophobia
What are the limitations of retinitis pigmentosa?
Progressive peripheral-full field loss
What are the limitations of Stargardt’s?
Detail loss (reading difficult)
Colour vision loss
Photophobia
Loss of eye contact
What are the limitations of optic atrophy?
Reduced colour vision
Decreased vision
Photophobia
Mobility
