05

Question 1

Cornea and lens percentage of focusing

Answer 1

70% and 30%

Question 2

What is accommodation

Answer 2

Ability to focus by changing the shapes if the lens
Near objects-thickens , far- flattens
Fatigue temporarily affects accommodation

Question 3

Retina

Answer 3

Inner lining if the eye containing light sensitive cells cones and rods

Question 4

Photoreceptors

Answer 4

Cones colour sensitive, clarity contrast work best in light, vision through cones=photopic vision
Rod- sensitive to low level light and movement. Used for peripheral vision and night vision. Vision through rods=Scotopic vision

Question 5

Fovea and optic nerve , cones and rods amount

Answer 5

Fovea all cones
Optician nerve none for each

Question 6

Extraocular muscles

Answer 6

Saccade- sudden,jerky movements of the eye to scan.
Attention-moving of eyes to place image over fovea
Pursuit-eyes visually track moving object

Question 7

Visual field

Answer 7

= central + peripheral vision
120 deg left to right
150 up down

Question 8

Visual acuity

Answer 8

Being able to resolve detail
Depends on th density of the photoreceptors
Densest area is around the fovea

Question 9

To what dist is binocular vision effective and outside of that how can we infer

Answer 9

60m /200ft
Colour contrast size and rate of movement

Question 10

Dark and light adaption time

Answer 10

Dark to light about 10 seconds
Cones light to dark 7-9 min
Rods Light to dark- 30min

Question 11

How to prevent empty field myopia

Answer 11

Use short, sharp scans