Lecture 21

Question 1

dual theory of light

Answer 1

• a wave and stream of particles

- travels light a wave made of photons

Question 2

photons

Answer 2

concentrated light energy

Question 3

wavelength influence _____

Answer 3

colour

Question 4

what is frequency

Answer 4

number of waves per second

Question 5

what has more energy, blue or red light

Answer 5

blue

Question 6

reflection

Answer 6

bouncing of light rays of a surface

Question 7

absorptions

Answer 7

transfer of light energy to a particle or surface

Question 8

what colour absorbs all wavelengths

Answer 8

black

Question 9

transmission

Answer 9

the moving of light waves through a material.

Question 10

refraction

Answer 10

bending of light rays when it travels from one medium to another

Question 11

scattering / diffraction

Answer 11

light dispersed in irregular fashion

Question 12

how long is the eye

Answer 12

1 inch

Question 13

what is the eye surrounded by

Answer 13

sclera (white we see)

Question 14

what provides the most refractive part of eye

Answer 14

cornea

Question 15

what provides nutrients to the cornea and lens

Answer 15

aqueous humour (nutrients and oxygen)

Question 16

what keeps eye round

Answer 16

pressure from fluid

Question 17

what are the sensory receptors of vision

Answer 17

rods and cones

Question 18

what controls lens

Answer 18

zonule of zin fibers

Question 19

schematic eye

Answer 19

cornea
aqueous humour
lens
vitreous humour

Question 20

what are 2 most refractive structures

Answer 20

cornea

lens

Question 21

what is a emmetropic eye

Answer 21

optically normal eye

Question 22

why cant we see things that are very close to eye

Answer 22

lens and cornea do not have enough refractive power to converge rays

Question 23

lens accomodation

Answer 23

change in curvature of lens in response to visual stimuli distance

Question 24

what is limit of accommodation for most young people

Answer 24

7cm (near point)

Question 25

lens power equation

Answer 25

(P)= 1/f

(f) is focal distance

Question 26

diopter

Answer 26

a unit measurement of the optical power of the lens

Question 27

what has more refractive power fat or thin lens

Answer 27

fat lens (closer object)

Question 28

retinal is age is flipped

Answer 28

vertically and horizontally

Question 29

where is retinal image more blurry

Answer 29

edges due to lens abbreviations

Question 30

hyperopia

Answer 30

• far sightedness
• cornea not curved enough or eyeball too short
• focal point is behind the lens
• treat with a complex lens, converge light rays more

Question 31

myopia

Answer 31

• nearsightedness
• cornea is too curved or eyeball is too long
• focal point in front of retina
• lens cannot flatten enough
• treat with concave lens, cause rays to refract outwards so eye can correct

Question 32

how much of population have “abnormal” eyes

Answer 32

over half

Question 33

presbyopia

Answer 33

• age related hardening of the lens and reduction in elasticity of the capsule the encircles lens
• affects everyone
• can be treated with convex or bifocal lenses

Question 34

astigmatism

Answer 34

• lack of symmetry in the curvature of the cornea
• causes blurred retinal image along affected direction only
• treated with special lenses that correct refractive deficit
• have trouble seeing things near