B10.6 Common problems of the eye

Question 1

What is accommodation?

Answer 1

Process of changing the shape of the lens to focus on near or distant objects

Question 2

What happens in order to focus on a distant object?

Answer 2

Ciliary muscles relax so the suspensory ligaments are pulled tight and the lens if pulled flat and thin - It refract light rays slightly so they are focused on the retina - due to the light travelling from distant objects are almost parallel rays

Question 3

What happens in order to focus on near objects?

Answer 3

The ciliary muscles tighten and the suspensory ligaments loosen. The lens is thicker and more curved. Refract light rays strongly so they are focused on the retina

Question 4

Why does accommodation get more difficult as you grow older?

Answer 4

Due the lens hardening

Question 5

What is myopia?

Answer 5

Short sightedness

Question 6

What is hyperopia?

Answer 6

Long sightedness

Question 7

What happens if you have myopia?

Answer 7

You can see close objects in focus but distant objects look blurred - due to the light focusing in front of your retina so images that actually land on your retina are out of focus and blurry

Question 8

Why does myopia occur?

Answer 8

Due to the lens that is too curved or a particularly long eyeball

Question 9

How can Myopia be treated?

Answer 9

Wear glasses with a concave lens that spread out light from a distant object before it reaches the eye. This means the thicker lens can bring it into perfect focus on the retina

Question 10

What happens if you have Hyperopia?

Answer 10

You can focus clearly on distant objects but close objects appear blurred

Question 11

Why does Hyperopia occur?

Answer 11

Maybe a result of a lens that is too flat or thin or a particularly short eyeball - as a result, the lens cannot refract the rays of light strong enough. The light is focused behind the retina

Question 12

How can Hyperopia be treated?

Answer 12

Using a convex lens. Bring out light rays together more before they reach the eye itself. Now the thinner lens can bring the rays of light into perfect focus on the retina

Question 13

How can contact lenses overcome the problems of Myopia and Hyperopia?

Answer 13

Lenses placed on the eye - do the same job as conventional glasses and can make life much easier for playing sport and general activities

Question 14

What are the issues with contact lenses?

Answer 14

They have to be kept sterile as they are removed overnight to prevent eye infections
Soft lenses do not last as long even though they are comfortable

Question 15

How can laser eye surgery overcome the problems of Myopia and Hyperopia?

Answer 15

Lasers are used to treat myopia by reducing the thickness of the cornea so it refracts the light less strongly - this means lens now focus distant light on the retina instead of in the front of the retina

Lasers are used to treat Hyperopia by changing the curve of the cornea so it refracts light from close objects more effectively

Question 16

How can replacement lenses overcome Myopia and Hyperopia?

Answer 16

Add another lens inside the eye itself to correct the visual defect permanently

In one way a permanent contact lens is implanted into the eye and the natural lens is left in place

In another way the faulty lens is replaced by an artificial lens.

Question 17

What are the issues of replacement lenses?

Answer 17

Can damage the retina and can cause infections