B10.6 - Problems With The Eye (Finished) Flashcards
What is accommodation?
The process of changing the shape of the lens of the eye to focus on near or distant objects
What problem happens to the lens as people get older?
It hardens so accommodation gets harder
To focus on a distant object what happens in the eye?
1) Ciliary muscles relax
2) so suspensory ligaments are pulled tight
3) so lens is made flat and thin
4) This makes it refract light less
What shape does the lens need to focus in a far object?
Flat and thin
What shape does the lens need to focus on a near object?
Thick and rounded
What happens when the eye needs to focus on a near object?
1) ciliary muscles contract
2) so suspensory ligaments slack
3) so lens becomes thick and rounded
4) This increases the amount by which it refracts light
Where is the light focused if you have myopia?
In front of the retina
How is someone’s vision with myopia?
They can see close objects clearly, but distant ones blurred
What distance can someone with Hyperopia see well at?
They can see distant objects clearly but near ones not so well
Where does light focus if you have Hyperopia?
Behind the retina
What lens is used to help people with Myopia and how does it refract light?
A concave lens, refracts light outwards, lens curves inwards
What lens is used to help people with hyperopia and how does it refract light?
Convex, refracts light inwards, lens curves outwards
What are contact lenses?
Thin lenses that sit on the surface of the eye and are shaped to compensate for the fault in focusing, correcting vision
What are the pros of contact lenses?
- lightweight
- invisible
- convenient
How does laser eye surgery work?
A laser vaporises tissue to change the shape of the cornea which changes how it refracts light
