Vision In Older Adults

Front 1

Sclera

Back 1

Dense, white, opaque other layer that is continuous with the cornea (whites of eyes)
Tough fibrous, protective tissue.
Prevents scattered light from entering the eye.
Protects the eye.

Front 2

Cornea

Back 2

Primary function: to refract light onto the focal point on the retina.
Highly transparent, avascular protective membrane that allows light to pass through to the retina.
Light is bent and refracted to properly focus on the receptors in the back of the eye.
High water content.

Front 3

Uveal tract

Back 3

Highly vascular middle layer of the eye that provides the blood supply and nutrition ot the other 2 portions of the eye.
Control light absorption.
Secrete the aqueous humour.

Front 4

Lens

Back 4

Focuses light on the retina by relaxing and contracting muscles.
Changes the shape of the lens, making it thicker or thinner.
Vascular.
Colorless.
Transparent.
Suspended behind iris.
Over time, thickens.

Front 5

Iris

Back 5

Contrast sensitivity (ability to discriminate b/w an object and its background)
Pigmented portion of the ey.
Purpose is to regulate the amount of light entering the eye through dilation and constriction of the pupil.
Circular membrane suspended behing the cornea and immediately in front of the lens.

Front 6

Vitreous Humor

Back 6

Clear, avascular gelatin making up 2/3 of the volume and weight of the eye.
Helps maintain shape and transparencies of the eye.
Build up of this contributes to intraoccular pressure.

Front 7

Retina

Back 7

Semitransparent.
Continuous w/ optic nerve
Photo-receptors that are "antennae" for visual system.
Houses Rods and cones.
Receives visual images.

Front 8

Cones

Back 8

Color sensitive
Visual acuity
color vision in bright light.

Front 9

Rods

Back 9

Peripheral vision, esp. in dim room.
Black and white vision.
RODS AND CONES CONTAIN PHOTOPIGMENTS THAT PRODUCE NERVE STIMULATION WHEN LIGHT STRIKES THEM.

Front 10

Optic Disc

Back 10

Region where retina meets the optic nerve.
Contains no light receptors, therefore is known as a natural "blind spot."

Front 11

Macula

Back 11

Oval, yellowish spot to the side of the optic disc.
Contains fovea, largely composed of cones and is the area of sharpest vision.
Key to focusing an area of the retina and is responsible for central vision.

Front 12

Changes associated with aging: Lens

Back 12

Thickens and becomes less elastic, limiting ability to change shape.
Changes interfere with ability to shift focues from distant to near objects (age-related far sightedness).
Yellows and becomes opaque causeing cooler colors to be difficult to see.
Pin-point opacities develop that produce dazzle from sources of bright light.
Better able to distinguish b/w bright colors.

Front 13

Presbyopia

Back 13

diminished ability to focus clearly on objects at a normal distance.
results in most adults needing reading glasses b/w 40-50

Front 14

Changes: iris

Back 14

eye colors fades.

Front 15

Changes: Vitreous Humor.

Back 15

Becomes less transparent.
Allows light to scatter instead of highly focused.
Floaters: loose cells and tissues casting shadows on retina.
Higher visual threshold: take smore light to be able to obtain info from environment.

Front 16

Changes: Pupil

Back 16

Pupil diameter decreases.
Direct pupil reaction to light tends to decrease resulting in much less light reaching retina.
RESULTS IN:
older people need more light for readings and getting around safely indoors.
Decreased ability to adjust to abrupt changes in lighting.
Both light and dark adaptation takes more time.

Front 17

Changes Associated with Aging.

Back 17

Sensitivity to glare: light scatters as a result of changes to cornea, lens and vitreous humor.
Loss of peripheral vision.

Front 18

Cataracts

Back 18

Opacities on lens as a result of protein build-up (sugery.)
Most common eye disorder related to aging.
May see halos around objects, experience blurred vision, decreased light and color perception.

Front 19

Cataracts Risk Factors

Back 19

High Blood Pressure.
Diabetes.
Use of corticosteroids.
Excessive exposure to sunlight.
Excessive consumption of alcohol.
Family history of cataracts.

Front 20

Glaucoma

Back 20

Increased Pressure in eye leads to degeneration of optic nerve and blindness if not treated.
Older women most at risk.
Can result in loss of peripheral vision.
Occurs slowly over time.

Front 21

Primary Open Angle Glaucoma (POAG)

Back 21

Most predominant.
Degenerative changes in the eye result in increased pressure slowly over time.
Medication and topic cream prescribed to inhibit vitreous humor production.

Front 22

Primary Angle Closure Glaucoma (PACG)

Back 22

Results from thickening of the lens causing closure of the duct that allows fluid to drain out.
Results in eye pain, clouded vision, nausea, and vomiting.

Front 23

Secondary Glaucoma

Back 23

Pathological process blocks the flow vitreous humor from eye.

Front 24

Causes of Glaucoma

Back 24

Inflammation
Diabetes
Tumors.

Front 25

Diabetic Retinopathy

Back 25

Leading cause of adult blindness.
Nearly every diabetic has some form of this after 20 yrs of diabetes.
Small retinal blood vessels develop small aneurysms which cause hemorrages which block light and damage receptors.
Symptoms:
cloudy vision
seeing shower spots.
Treatment:
laser photocoagulation

Front 26

Macular Degeneration

Back 26

Severe loss of central vision.
Dry=no bleeding, no treatment.
90% of cases
Cells in Macula atrophy.
Wet=bleeding.
injection into eye to keep vessels from bleeding, growing; laser treatment.
Will become functionally blind if untreated.
Need for increasingly bright light when reading or doing close work.
Printer words that appear distorted or increasingly blurred.
Straight lines will appear bent/curved.
Colors that seem washed out or dull.
Gradual haziness of overall vision.
Difficulty seeing when moving from bright room to dimly lit room.

Front 27

Macular Degeneration Causes.

Back 27

Genetics
Smoking
Cardiovascular Disease.
Long-term sunlight exposure.

Front 28

Low vision

Back 28

Corrected visual acuity b/w 20/70 and 20/200
Diagnosed when all other treatmens are unsuccessful.
Can be central or peripheral.
Stroke can result in loss of peripheral vision.

Front 29

Ocular Diseases

Back 29

Major implication of central vision loss is difficulty w/ detail discrimination (reading, hearing aid parts)(most often seen as result of macualar degen.)
Peripheral vision loss may result in difficulty w/ orientation and mobility.
Emotional and Social Implications.