Pathophysiology of eye and care Flashcards
80% of vision loss is causes by 5 conditions
- Age related macular degeneration (AMD)
- Cataract
- Diabetic retinopathy
- Glaucoma
- Under-corrected and uncorrected refractive error
What percentage of vision loss is preventable and treatable?
75%
People with vision impairment are at a greater risk of suffering from secondary conditions (6)
- Falls
- Depression
- Early special accommodation
- Increased risk of hip fracture
- Increased early mortality
- Social isolation
Vitreous body is filled with vitreous fluid (humor) purpose
Allows the eye to keep its shape
Conjunctiva
A thin mucus membrane that covers the eye
Bulbar conjunctiva with sclera beneath
The white of the eye
Limbus
The junction of cornea and sclera
How does the lens work?
Lens projects inverted image on to retina which produces a signal and sends to the brain to invert it back.
2 types of photosensitive cells
Rods (120 million) and cones (6 million)
Rods are sensitive to…
light
Cones are sensitive to…
colours
Purpose of retinal blood vessels
Nutrition and blood supply to the retina.
Where in the fovea?
The centre of the macula
What is in the fovea?
Cones (colours)
What is in the periphery of the retina?
There are more rods and it becomes slightly thinner
Retinal detachment from bleeding in the eye can cause…
blindness
What is retina detachment?
The retina is lifted or pulled from normal position. Usually occurs when small areas of the retina become torn.
What is the macula?
The area next to optic disc that defines fine details at the centre of visual field
What is age-related macular degeneration (AMD)?
A chronic degenerative condition that affects the central vision; not enough blood supply to area.
What part of the eye is affected in age-related macular degeneration (AMD)?
The macular, disappearance of central vision due to deterioration of pigment layer of retina
What causes degeneration of the macular?
Abnormal blood vessels leaking fluid or blood into the macular.
How does age-related macular degeneration affect the vision?
Black/dankness at the centre of vision.
Functional implications of AMD (7)
- Difficulty distinguishing people’s faces
- Difficulty with close work
- Perceiving straight lines as distorted or curved
- Unable to differentiate between the footpath and road
- Difficulty identifying the edge of steps if there is no colour contrast
- Unable to determine traffic light changes
- Difficulty reading, with blurred words and letters running together
What is a cataract?
A cataract is the clouding of the lens inside the eye. With a cataract, light is scattered as it enters the eye, causing blurred vision; gradual deterioration of lens.