Old Age and Eye Development Flashcards
Which age group is the fastest growing?
85 year old
What are the significant neural changes due to old age?
Decreased blood flow
Brain gets smaller
Number of neurons decreases
At what age do vehicle accidents significantly increase?
75
What happens to the pupil with age and what problems does this cause?
Pupil gets smaller with age and thus creates problems seeing at night and increased glare sensitivity. To correct this we need more light but more light will cause more constriction.
How long is glare recovery of the pupil after being exposed to bright light?
In a 65 yo, 18 seconds. In a 90 yo about a minute.
What does the ciliary body do in accommodation?
The ciliary body will constrict and push on the unmoving, unchanging lens zonules and thus make the lens fatter and increase its index of refraction
What does the yellowing of the lens do to vision?
It causes the person to see yellow, orange and red better than blue green and violet because yellow scatters those colors with a smaller wavelength.
It can also mess with depth perception cues since contrast sensitivity is weakened.
What happens to retina thickness with age?
It thins. Thought to be due to the decrease in neurons and shortening of the outer segments of the photoreceptors that contain the opsin.
What are the rod and cone changes in the retina with age?
Starting in the 4th decade the cones of the fovea and equator are decreasing in number. In the 60s-90s there isn’t much change in the FOVEAL cones, however at 90, they start to shrink. Much more peripheral cones are lost faster than in the fovea.
Rods start to shrink in the 9th decade, but before then not much was going on with the rods.
Where does Lipofuscin come from?
It is phagocytized in the photoreceptor outer segment
Where does Melanin come from?
The melanin is believed to originate from the autophagocytosis of lysozomes in the RPE itself.
Where do Drusens form and what type is the most common?
Drusens form between the RPE and Bruch’s Membrane. The most common type (8-%) is are hard drusens. They are small , hard and round are are age related. The soft drusens are more pathologically related (AMD) and are without a well defined border.
What is the normal range of anisometropia in old people?
- 4 D for under 50
0. 9 D for 85+
When does color vision go?
Around 65 years old. They have blue/yellow deficits which are very rare in young people.
When does VA and Contrast Sensitivity and color vision go?
Around 65 yo.
