Senescence And The Eye Flashcards
Aging changes in the cornea
- DECREASED WOUND HEALING (long revocery from surgery)
- breakdown in the barrier function of the corneal epithelium
- decreased sensitivity
Aging changes in corneal endothelium
- DECREASE IN CELL DENSITY
- polymegathism (greater than normal variation in size)
- pleomorphism (increased variability in size and shape)
Hassall-Henle bodies
Endothelial indentations Decemets membrane thinckens Peripheral Use retro or specular Assymptomatic Rule out Fuch's Drop out of endothelial
Hudson-Stahli line
Iron deposits in epithelial cell cytoplasm
Limbal girlde of Vogt
Degeneration of bowmans layer
-3 and 9 o clock
Series of white deposits
The most common aging change in the cornea
Corneal arcus
What are the deposits in corneal arcus
Cholesterol and cholesterol esters
Clinical significance of corneal arcus
There is no clinical significance in elderly persons, but in those under age 40, hyperlipidemia should be suspected
How many people will you see with arcus that are over age 80
About 100%
Is corneal arcus bilateral or ipsilateral
Bilateral
Krukenberg’s spindle
Pigment deposits on the posterior cornea with a vertical orientation, increases with age
Aging changes in the sclera
- fatty deposits may cause the sclera to appear yellow
- concentration of certain proteoglycans is decreases, causing scleral thinning and loss of elasticity
Anterior chamber changes with age
- narrows
- volume decreases
- narrowing mroe significant in women and may be related to the higher incidence of the angle closure glaucoma in elderly women
- decrease in aqueous production
Age related IOP *
No age related increase in IOP seen in healthy individuals with pressure below 22mmHG
AGE NOT A REASON FOR HIGH IOP
Aging changes in the iris
The dilator muscle becoems atrophic and the sphincter muscle becoems sclerotic, making it more difficult to dilate the older pupil pharmacology
Why is there a loss of pigment from the epithelium is evident at the pupillary margin and on transillumination
The root is thinner, so there may be more pigment loss there and transillumination defects there
Aging changes in ciliary body
- CT increases
- no significant correlation between loss of ciliary muscle contractile ability and age**
- aqueous decreases
- volume of anterior chamber decreases
What is the significance of loss of ciliary muscle contractile ability and age
There is no correlation!
Aging changes in the crystalline lens
- clinical manifestations of aging are presbyopia and cataract formation
- use UVR-absorbing lenses
When are cataracts expected to more common
In those exposed to greater levels of sunlight
When does the crystalline lens stop growing
Never, grows throughout life
When does the increase in the lens size occur the most
Between 8 and 40, accompanied by an increase 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
The gel volume decreases and the liquid volume increases, this process is known as vitreous liquefaction or vitreous syneresis
What forms floaters with age
As the dissolution of the HA-collagen complex occurs, the macromolecules 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?
Posteiror vitreous detachment caused by the traction from the collagen bundles to the vitreous
What happens when the vitreous pulls away from the optic nerve
If glial tissue is torn away with the vitreous, a circular condensation, Weiss’ ring (senile annular ring), may be visible within the vitreous
What is responsible for the clinical appearance of drusen
Calcification and deposits in the inner collagenous layer of Bruch’s
-as lysosomal activity in RPE decreases with age, atypical material (including lipofushcin) may accumulate in Bruch’s membrane
Age changes in lamina cribrosa
Changes inthe laminar pores in the aged lamina cribrosa may take the nerve fibers passing through the openings more susceptible to injury, contributing to an increased susceptibility to glaucomatous damage
Aging changes in the retina
- the foveal reflex dims because the ILM thickens
- the accumulation of debris in drusen are located in Bruch’s membrane of the choroid but are observed as pinpoint deposits in the retina
Ganglion cells loss and aging
Because an estimated 33-50% of CNS neurons are lost during lifetime, the number of retinal neurons will decrease, with ganglion cell loss especially noted in the fovea
The number of retinal pigmented epithelial cells and aging
Reduced from 4000/mm^2 to 2000/mm^2
What is an age related degeneration of RPE and Bruch’s membrane and what is the cause of it
Peripapillary choroidoretinal atrophy
-caused by attenuation of the peripapillary circulation
Neuroretinal rim tissue and age
Decreases and ther vertical optic cup diameter and the area of the optic cup both increases
-needs to be considered when assessing the optic nerve head for glaucoma
Aging changes in the EOMS
Both horizontal rectus muscles are displaced inferiroly with age, with the medial rectus displaced more than the lateral rectus
What is the cause of a constant partial depression and may contribute to the imparted ability to elevate the eyes often observed in elderly persons, predisposing them to an incomitant strabismus
Both horizontal muscles are displaced inferiorly with age, with the medial rectus displaced more than the lateral rectus
Aging changes in the orbital adnexa
The eyebrow position heightens in both genders with increasing age, skin looses elasticity in the lids
-more pronounced changes in lid margin position, including ectropion and entropion, increase in incidence with age related changed in the orbicularis muscle tone
Aging changes in the lacrimal system
-tearing may be caused by eversion of the lower punctum due to eyelid position or by stenosis of the passages in the lacrimal drainage systems; bot occur more frequently in elderly persons
Tear secretion and age
Some studies find that basal rate of tear secretion diminishes after age 40, contributing to dry eye, the incidence of which increases with age
Vascular engorgment at lid margin and age
The incidence of vascular engorgemtn at the lid margin and plugged meibomian gland pores also increases with age
Effect of aging on ocular circulation
Endothelial dysfunction can occur with age and can result in increased vascular tone, a reduction in vessel distensibility, and a decrease in tissue perfusion
Aging and VF
Age is accompanied by a decrease in the extent of the VF, caused both by loss of cells and by a decrease in the transparency of the ocular media
Determining speed of moveing objects and age
The inability to accurately determine the speed of moving objects contributes to a higher incidence of car accidents among the elderly
