Vision 1 & 2

Question 1

What is refraction?

Answer 1

The bending of light as it passes from one medium to another

Question 2

Which structures in the eye allow for refraction?

Answer 2

Cornea and lens

Question 3

What is accommodation?

Answer 3

The changes occurring in both eyes as it focuses from a distant object to a close object

Question 4

What three things comprise accommodation?

Answer 4

Lens change shape, pupil constricts and eyes converge

Question 5

Which muscle allows the lens to become thicker

Answer 5

ciliary muscles

Question 6

What effect does thickening the lens have on the focus?

Answer 6

It allows focusing on close objects

Question 7

Which nerve fibres causes ciliary body contraction

Answer 7

Parasympathetic

Question 8

What is convergence?

Answer 8

The turning in of the eyes when focussing on an object up close

Question 9

Which muscles are responsible for convergence of the eyes?

Answer 9

Medial rectus muscles

Question 10

What is myopia?

Answer 10

Short-sightedness

Question 11

What is hyperopia?

Answer 11

Long-sightedness

Question 12

What is astigmatism?

Answer 12

Non spherical curvature of the cornea or lens

Question 13

What is presbyopia?

Answer 13

Long-sightedness of old age

Question 14

What happens to a persons vison in shortsightedness?

Answer 14

Close objects look clear and distant objects appear hazy

Question 15

What is the most common cause of short-sightedness?

Answer 15

Eyeball is too long, making the image form in front of the retina

Question 16

What are the symptoms of short-sightedness?

Answer 16

Headaches, not able to see distant objects, divergent squint in infants and preverbal children and loss of interest in sports/people in adults

Question 17

How is short-sightedness corrected?

Answer 17

Biconcave lenses (glasses or contact lenses) or laser eye surgery

Question 18

What happens to a persons sight in far-sightedness?

Answer 18

Close objects look hazy and distant objects appear clear

Question 19

What is the cause of far-sightedness?

Answer 19

Eyeball too short or cornea + lens too flat making the image appear behind the retina

Question 20

What are the symptoms of far-sightedness?

Answer 20

Eyestrain and convergent squint in children/toddlers

Question 21

How is far-sightedness corrected?

Answer 21

Biconvex glasses, contact lenses or laser eye surgery

Question 22

What happens to a person’s vision in astigmatism?

Answer 22

Close and distant objects appear hazy

Question 23

What is the cause of astigmatism?

Answer 23

The surface of the eye has different curvatures in different mediums

Question 24

What happens to vision in presbyopia?

Answer 24

Seeing near objects becomes difficult

Question 25

What is the cause of presbyopia?

Answer 25

With age the lens gets less mobile/elastic and when the ciliary muscle contracts it is less able to change shape

Question 26

How is presbyopia corrected?

Answer 26

Biconvex "reading glasses"

Question 27

What is phototransduction?

Answer 27

The conversion of light energy to an electrochemical response by the photoreceptors (rods and cones)

Question 28

What is rhodopsin made up of?

Answer 28

Opsin + 11-cis Retinal

Question 29

How does bleaching of the visual pigment result in phototransduction?

Answer 29

Phototransduction

Question 30

What role does vitamin A play in the visual pigment?

Answer 30

Visual pigment regeneration

Question 31

Where do all fibres from the eye pass?

Answer 31

Through the optic nerve to the optic chiasm

Question 32

What happens to the fibres at the optic chiasm?

Answer 32

The medial/nasal fibres cross to the opposite side

Question 33

What fibres does the optic tract contain?

Answer 33

Fibres from the temporal half of the ipsilateral eye and the nasal fibres from the contralateral eye

Question 34

Where do the optic radiation fibres go?

Answer 34

Primary visual cortex in the occipital lobe

Question 35

Name the six extrinsic ocular muscles of the eye

Answer 35

Medial rectus, lateral rectus, inferior rectus, superior rectus, superior oblique and inferior oblique

Question 36

Where do the recti muscles of the eye arise from?

Answer 36

An annular fibrous ring at the apex of the orbit

Question 37

Where does the superior oblique muscle arise from?

Answer 37

Roof of the orbit posteriorly

Question 38

Where does the inferior oblique muscle arise from?

Answer 38

Floor of the orbit anteriorly

Question 39

What does the levator palpebrae superioris do?

Answer 39

It elevates the upper eyelid

Question 40

Which muscle is supplied by the trochlear nerve?

Answer 40

Superior oblique

Question 41

Which muscle is supplied by the abducent nerve?

Answer 41

Lateral rectus

Question 42

Which nerve innervates the extrinsic muscles of the eye (apart from LR and SO)?

Answer 42

Oculomotor nerve

Question 43

Where is constrictor pupillae found?

Answer 43

At the pupillary border in the iris

Question 44

Where does the dilator pupillae lie?

Answer 44

Radially in the iris

Question 45

What is the innervation of the ciliaris and constrictor pupillae muscles?

Answer 45

Parasympathetic fibres from the oculomotor nerve

Question 46

What is the innervation of the dilator pupillae muscle?

Answer 46

Sympathetic fibres