Senescence And The Eye - Block 8 Flashcards
What is not a reason to put in the chart when the patient is having visual issues
Old age
Age is accompanied by a increase/decrease in the extent of the what??
Decrease in visual field
What is the decrease in visual fields due to age caused by?
- loss of cells
- decrease in transparency of the ocular media
What contributes to a higher incidence of car accidents among the elderly?
The inability to accurately determine the speed of moving objects due to aging within the visual pathway
What effect would aging have on the cornea?
Decreased wound healing
What effect would aging having on the corneal endothelium?
Decrease in cell density
The most common aging change in the cornea
Corneal arcus
Coronal arcus are what kind of deposits?
Cholesterol and cholesterol esters
Is there a clinical significance in elderly persons?
No
In people under the age of 40, what should be suspected when you see corneal arcus?
Hyperlipidemia
What are the aging changes in the sclera?
Fatty deposits may cause the sclera to appear yellow
Concentration of certain proteoglycans is decreased, causing scleral thinning and loss of elasticity
What are the age related changes in the anterior chamber?
Anterior chamber width narrows
In who is the narrowing of the anterior chamber angle most significant?
In women
May be related to the higher incidence of angle-closure glaucoma in elderly women
Is there an age-related change in IOP?
No age-related increase in IOP is seen in healthy individuals with pressures below 22 mmHg
What happens to the sphincter and dilator muscles of the iris in regards to aging changes?
Dilator = becomes atrophic Sphincter = becomes sclerotic
When the dilator muscle of the iris becomes atrophic and the sphincter muscle becomes sclerotic due to aging, what becomes more difficult?
Makes it more difficult to dilate the older pupil pharmacologically
What’s the significance between loss of ciliary muscle contractile ability and age?
No significant correlation
What are some age-related changes of the crystalline lens?
Presbyopia
Cataract formation
What do you recommend the pt to use when they ask how they can prevent cataracts
-can’t prevent, but can try to wear UVR-absorbing lenses when outdoors to help b/c incidence of cataracts is higher in those exposed to greater levels of sunlight
Does the lens grow throughout life?
Yes
When does the majority of the increase in thickness of the crystalline lens occur? What accompanies it?
Between ages 8 and 40
Accompanied by an inc in surface curvatures, a forward movement of the center of the lens, and a decrease in anterior chamber depth
Age related changes in the vitreous, where the gel volume decreases and the liquid volume increases
Vitreous liquifaction or vitreous syneresis
What happens to the hyaluronic acid-collagen complex in the vitreous, due to age?
The complex goes through dissolution, the macromolecule moves out of the collagen network, causing the fibrils to coalesce into fibers and then into bands
What is one of the most common abnormalities that occurs at the posterior retinal-vitreous interface?
Posterior vitreous detachment caused by traction
This becomes visible within the vitreous when the glial tissue is torn away from the vitreous
A circular condensation, known as Weiss’ ring (senile annular ring)
What is responsible for the clinical appearance of drusen?
Calcification and deposits in the inner collagenous layer of the choroid
Increases in number with age
As lysosomal activity in the RPE decreases with age, what happens?
Atypical material (including libofuscin) may accumulate in Bruch’s membrane
What effects will happen to the nerve fibers that pass through the lamina cribrosa when the change in the laminar pores due to age occur?
The become more susceptible to injury, contributing to an increased susceptibility to glaucomatous damage
Why does the foveal reflex dim?
B/c the internal limiting membrane thickens
What are observed as pinpoint deposits in the retina?
Accumulations of debris in drusen that are located in Bruch’s membrane of the choroid
How many neurons of the CNS are lost during lifetime? What will happen to retinal neurons?
33%-50% are lost
Retinal neurons will decrease, with ganglion cell loss especially noted in the fovea
Number of retinal pigmented epithelial both before and after age-related changes to the retina
4000/mm^2 to 2000/mm^2
Pale, temporal crescent, that’s an age-related degeneration of RPE and Bruch’s membrane, and may be caused by attenuation of the peripapillary circulation
Peripapillary chorioretinal atrophy
What needs to be considered when assessing the optic nerve head for glaucoma?
Decrease in neuroretinal rim tissue, and the vertical optic cup diameter and the area of the optic both increase
What can be the cause of aging in the extraocular muscles?
Constant partial depression
May contribute to the impaired ability to elevate the eyes often observed in elderly persons, predisoing them to an incomitant (noncomitant) strabismus
