Visual Conditions Flashcards
Visually impaired:
- Near-normal/mild
- Moderate
- Severe
- Profound
- Near-total blindness
- Total
Blind
No Light perception
Legal Blind
- Technically: 20/200
- Such a label is counterproductive in efforts to convince those who have low vision that their remaining vision is STILL useful!
Low Vision
Technically: 20/70
(and/or visual field constriction of 20 or more)
-Vision deficits that can be corrected with regular glasses, contact lenses, medicine or surgery.
-“If you are wearing glasses, but still have problems seeing faces, details, cooking, fixing things around the house, matching colors, or reading signs or books, then you may have low vision.”
“Blinding Eye Disease”
- 2nd only to cancer as the “most-feared” disease.
- Visual Impairments afflicts 1 out 10 over 65 years of age, and 1 out of 4 over 75.
- By 2040, 25% of US population will be over 65 years old.
Visual Conditions Prevelance
- 3rd leading cause of disability in adults over age 70
- Estimated 14 million sufferers
- Predictions: Double within the next 10 years (2020)
Populations and Vision Problems
- Correctable vision impairments
- Uncorrectable vision impairments and low vision
- Neurologically based visual dysfunction
Correctable vision impairments
Refractive errors including myopia, hyperopia, astigmatism, and presbyopia
Uncorrectable vision impairments and low vision
May include visual acuity and visual field deficits that impact a persons ability to complete everyday activities
Neurologically based visual dysfunction
Visual problems include eye alignment, visual fields, and visual inattention.
Vision is not just an input system, it’s also an output system
- Sensory, Motor, Cognition
- VMI
- Balance
Visual perception impairment may occur due to…
Deficits in foundational sensory or motor components.
Visual perception impairments may lead to…
Faulty learning.
How is the image placed on the retina?
Image is placed upside down and inverted on retina, light converts to electicity and travles to the brain to primary visual cortex and we find meaning.
Sensory Component of Vision
Features of the iamge are identified and recognized, compared and assigned meaning:
Cogntivie Component of Vision
Eyes work as team, move in coordinated smooth pattern, point at the same target produce unified image:
Motor Component of Vision
Vision and Body Coordination work together for tasks: Visual Motor Integration
How is balance controlled by vision?
Balanceis controlled through signals to the brain from youreyes, the inner ear, and the sensorysystemsof the body
Warren’s Model (OT)
Three Distinct Stages of visual functioning:
Colenbrander’s Model (ophthalmologist
Optical: “Eyeball” relate
Retinal: “Light to Electricity” Phase
Neural: “Mental Picture”, “Cognitive Visual Dysfunction”
Sensory Component (Components of Vision)
- Visual Acuity
- Contrast Sensitivity
- Visual Field
- Peripheral
Motor Component (Components of Vision)
- Oculomotor Function
- Saccades
- Smooth Pursuits
- Convergence
- Binocular Vision
- Eye Alignment
Cognitive Component (Components of Vision)
- Visual perception
- Visual Attention
- Visual Search
- Other VP skills
Most Common Causes of Vision Problems
- Age-Related Macular Degeneration
- Glaucoma
- Diabetic Retinopathy
- Stroke
- Brain Injury
