The Eye

Question 1

What is the shape of the lens caused by

Answer 1

Cilary muscles and suspensory ligaments

Question 2

What happens when you look at near objects

Answer 2

Ciliary muscles tighten

Suspensory ligaments relax

Question 3

What happens when you look at far away objects

Answer 3

Cilirary muscles relax

Suspensory ligaments tighten

Question 4

Explain long sightness

Hyperopia

Answer 4

They are unable to focus on close objects

This is because the light rays are focused behind the retina due to the eyeball being to short

Convex lens is used to converge the light rays onto the retina

Question 5

Explain short sightedness

Myopia

Answer 5

Unable to focus on objects at a distance . This occurs when the lens refracts the light to much or the eye is too long

The light rays converge before the eye

Concave lens is used to diverge the rays onto the retina

Question 6

How does the eye adjust to different levels of light

Answer 6

Light receptors detect very bright light . A reflex is triggered that makes the pupils smaller , the circular muscles contract and radial muscles relax

When there is dim light radial muscles contract and circular muscles relax making the pupil wider.

Question 7

How do contact lenses fix sight

Answer 7

They are thin lenses that sit on the surface of the eye .
They are shaped to compensate the fault for focusing light.
They are popular because they are light weight and invisible
They are convenient for sports and other physical activities
There are 2 types . Soft and hard lenses
Soft lenses are more comfortable but pose a greater risk of infection than hard lenses .

Question 8

Explain laser eye surgery

Answer 8

A laser vaporises tissue changing the shape of the cornea this changes the way the light rays are refracted onto the cornea

Slimming the tissue improves short sight and changing the shape helps long sight

Howver like all surgeries there are risks . Such as infections or the eye reacting with the laser in a negative way

Question 9

Explain replacement lens surgery

Answer 9

The natural lens is removed and an artificial lens , made of clear plastic is inserted in it’s place .

Due to its invasive nature the surgery contains risks , it could potentially cause the loss of sight due to damaging a retina