Vision

Question 1

What is the basic structure of the eye?

Answer 1

Iris, lens and retina

Question 2

Describe the cornea

Answer 2

A clear window at the very front of the eye which allows light to enter
Responsible for 70-80% of refraction (focusing ability) and causes the light to bend

Question 3

What is the function of the iris?

Answer 3

To control the amount of light that enters the eye

Question 4

What is the function of the pupil?

Answer 4

To alter its size to control the amount of light that enters the eye

Question 5

Describe the lens

Answer 5

The lens is used for focus

The light passes through the lens after passing through the iris and pupil

Question 6

Describe the retina

Answer 6

Located at the rear wall of the eyeball

Made of complex layers of nerve cells connected to the optic nerve

Question 7

What are the two types of retina?

Answer 7

Cone and rod

Question 8

Describe the function of the cone

Answer 8

It functions in good light, detects fine details and distinguishes colours

Question 9

Describe the function of the rod

Answer 9

Good for detecting movement in the edge of the visual field

It is more sensitive to lower light levels

Question 10

What is the central retina known as and what does it do?

Answer 10

Fovea
Its receptors are all cones
It aids with the focus of the image

Question 11

The lens of the eye lets light through, what muscle can change its shape?

Answer 11

Ciliary muscles

Question 12

What is the factor if light adjustment that can be made by the pupil?

Answer 12

5:1

Question 13

What is important about the point where the optic nerve joins the back of the eye?

Answer 13

It is the location of the blind spot

Question 14

What does 20/20 vision mean?

Answer 14

Compares you to what a normal person can see at 20ft

Question 15

If the angular distance from the Fovea is 5 degrees, how much dies the acuity drop by?

Answer 15

50%

Question 16

What is the term for long sightedness and what is its corrective method?

Answer 16

Hypermetropia

Convex lens

Question 17

What is the term for short sightedness and what is its corrective method?

Answer 17

Myopia

Concave lens

Question 18

What are cataracts?

Answer 18

Clouded lens associated with aging

Question 19

What is astigmatism?

Answer 19

Misshapen cornea causing objects to appear irregular

Question 20

What is Glaucoma?

Answer 20

A build up on pressure of the fluid in the eye which causes damage to the optical nerve and may cause blindness

Question 21

What is presbyopia?

Answer 21

A form of long sightedness where the lens becomes less flexible and is unable to accommodate sufficiently
It comes with ageing

Question 22

What is the term when carbon monoxide builds up in the bloodstream, inhibiting the flow of O2 to the eyes?

Answer 22

Hypoxia

Question 23

What causes colour vision deficiency?

Answer 23

A defect in the colour sensitive cones in the retina

Question 24

How many percentages of men and women are affected by colour vision deficiency?

Answer 24

8% men

0.5% women

Question 25

What is the most common form of colour deficiency?

Answer 25

Red and green

Sometimes blue and yellow

Question 26

What is the correct term for colour blindness?

Answer 26

Colour defective vision