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Vision Changes in Elderly

Terms in this set (28)

Normal Age Related Changes of the Eye
1. Presbyopia
2. Decreased contrast sensitivity and colour saturation
3. Lens selectively absorbs more blue light
4. Increased dark absorption threshold
5. Increased light sensitivity
6. Decreased tear production
7. Changes in corneal toricity (i.e. arcus senilis)
Presbyopia

(accommodation problem)
- reduced ability to focus on near objects
- accommodation problem
- hardening of the crystalline lens capsule, because of modifications in cortical fibre cell cytoplasm and nuclear protein solubility
- atrophy of the ciliary muscles are the primary causes of lost accommodation
Decreased contrast sensitivity and colour saturation
- the crystalline lens becomes less clear and as a result, begins to scatter more light as one ages
- this scattered light reduces the contrast of the retinal image
The lens selectively absorbs more blue light (410 nm)
- because of the accumulation of yellow pigments in the lens
Increased dark absorption threshold
- the retina receives less light as one ages, because pupil size becomes smaller (senile miosis) and the crystalline lens becomes thicker and more absorptive
Increased light sensitivity
- dark adaptation (decreases in pupil size), recovery from glare (opacities in the aging lens and neural changes in the retina), reduction in number of cones at the fovea causes generalized reduction in colour vision
Decreased tear production
- also apart of normal aging
Changes in corneal toricity (curvature) causes alteration in refraction i.e. arcus senilis
(a.k.a. arcus senilis coreneae)
- white, gray or blue opaque ring in the corneal margin (peripheral corneal opacity) or white ring in front of the periphery of the iris
- not pathological
Visual impairments and blindness in the older person result from four main causes:
1. cataracts
2. macular degeneration
3. glaucoma
4. diabetic retinopathy
Cataracts

(clouding of the crystalline lens)
- clouding of the crystalline lens presents as painless, progressive, loss of vision can be unilateral or bilateral
Types of Cataracts

N. is central
S. is back
C. is outside
1. A nuclear cataract (white haze deep in central zone of lens)
2. A sub scapular cataract (back of the lens)
3. A cortical cataract (lens cortex; outside of lens)
Macular degeneration

(drusen deposits in pigmented epithelium)
- the most common cause of legal blindness in the elderly
- the development of drusen deposits in the retinal pigmented epithelium
- leading cause of central vision loss in older adults
- risk factors include smoking and excessive sunlight exposure
- there are wet and dry forms of macular degeneration
Glaucoma

(increased intraocular pressure)
- a potentially serious form of eye disease
- the majority of cases of glaucoma are open angle glaucoma (95%)
- increased intraocular pressure causing atrophy and cupping of the optic nerve head causing visual field deficits that can progress to blindness
- vision changes include loss of peripheral vision, intolerance to glare, decreased perception of contrast, and decreased ability to adapt to the dark
Open Angle Glaucoma

(clogging of drainage canals)
- primary glaucoma (accounts for 90% of all cases)
- caused by slow clogging of the drainage canals, resulting in increased eye pressure
Closed Angle Glaucoma

(mechanical blockades - peripheral iris)
- refers to disorder raised intraocular pressure (IOP) due to mechanical blockade, usually the peripheral iris, of the access drainage mechanism of the eye (the trabecular meshwork), with subsequent optic disk and visual field changes
- second leading cause of blindness
Diabetic Retinopathy

(end organ damage - diabetes)
- end organ damage from diabetes causing retinopathy and spotty vision
- risk can be reduced by tight blood sugar control
- starts as non-proliferative and progresses to proliferative that should be treated with laser photocoagulation
Signs of diabetic retinopathy (7)
1. micro aneurysms
2. dot and blot hemorrhages
3. flame shaped hemorrhages
4. retinal edema and hard exudates
5. cotton wool spots
6. venous loops and venous bleeding
7. macular edema
Micro aneurysms

(red dots in superficial layers)
- the earliest clinical sign of diabetic retinopathy; these occur secondary to capillary wall out pouching due to percyte loss
- they appear as small red dots in superficial retinal layers
Dot and blot hemorrhages

(red dots in deep layers)
- they occur as micro aneurysms in deep layers of the retina, such as the inner nuclear and outer plexiform layers
Flame shaped hemorrhages

(superficial splinter hemorrhages)
- superficial splinter hemorrhage that occur in the more superficial nerve fiber layer
Retinal edema and hard exudates
(allowing leakage of proteins and lipids)
- caused by the breakdown of blood retinal barrier, allowing leakage of serum proteins, lipids and protein from vessels
Cotton wool spots

(nerve fiber layer infarctions)
- nerve fiber layer infarctions from occlusion of pre-capillary arterioles; they are frequently bordered by micro aneurysms and vascular hyper permeability
Venous loops and venous bleeding

(reflect increasing ischemia)
- frequently occur adjacent to areas of non-perfusion; they reflect increasing retinal ischemia and their occurrence is the most significant predictor of progression to proliferative diabetic retinopathy (PDR)
Macular edema

(leading cause - impairment)
- leading cause of visual impairment in patients with diabetes
Common Conditions for the Eyes
1. hypertensive retinopathy
2. temporal arteritis
3. detached retina
Hypertensive retinopathy
- end organ damage from poorly controlled hypertension causing background and eventual proliferative retinopathy
Temporal arteritis
- autoimmune disorder that causes inflammation of the temporal artery
- it presents as malaise, scalp tenderness, unilateral temporal headache, jaw claudication, and sudden vision loss (usually unilateral)
Detached retina
- can occur in patients with cataracts or recent cataract surgery, trauma or be spontaneous
- presents as a curtain coming down across the vision
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