Anatomy + Physiology

Question 1

What are the three layers of the eye?

Answer 1

Fibrous (outer layer)
Uvea - vascular layer (middle layer)
Retina - photosensitive (inner layer)

Question 2

What are the two parts of the fibrous outer layer and what do they do?

Answer 2

Sclera - muscle attachment

Cornea - 2/3 of refractive power

Question 3

What are the three parts of the uvea (vascular) layer and what do they do?

Answer 3

Iris - pupil diameter
Ciliary body - controls iris, shape of lens + secretions of aqueous humour
Choroid - nutrition + gas exchange

Question 4

What are the three main parts of the retina (photosensitive) layer?

Answer 4

Retina
Macula
Optic disc

Question 5

Where is the anterior segment of the eye?

Answer 5

In front of the lens

Question 6

What are the two parts of the anterior segment?

Answer 6

Anterior chamber - between cornea and iris

Posterior chamber - between iris and suspensory ligaments

Question 7

Where is the posterior segment of the eye?

Answer 7

Behind the lens

Question 8

What does the posterior segment contain?

Answer 8

Vitreous body - contains vitreous humour

common location for ‘floaters’

Question 9

Which part of the eye is affected in a cataract?

Answer 9

Lens is clouded

Question 10

What is the limbus?

Answer 10

Corneo-scleral junction

Question 11

Where is aqueous fluid made and secreted from in the eye?

Answer 11

Made in ciliary body

Secreted from ciliary processes

Question 12

Where does aqueous fluid go once it is secreted, before it is reabsorbed?

Answer 12

Circulates within posterior chamber - nourishes lens

Then passes through the pupil into anterior chamber - nourishes cornea

Question 13

Where is aqueous reabsorbed?

Answer 13

Into scleral venous sinus (Canal of Schlemm) at iridocorneal angle

Question 14

What is the clinical significance of the iridocorneal angle?

Answer 14

Its the angle in ‘open-angle’ and ‘closed-angle’ glaucoma

Question 15

What is the arterial supply to the eye?

Answer 15

Ophthalmic artery - branch of internal carotid

Question 16

What is the arterial and venous supply to the retina and what is the clinical significance?

Answer 16

Central artery of the retina
Central vein of the retina

• end artery (no anastomosis to maintain viability if occlusion occurs)
• only vein draining the retina

Question 17

What is the fundus?

Answer 17

Posterior area of the retina where light is focused

Question 18

Which features can be seen when looking at the fundus?

Answer 18

Optic disc
Macula
Fovea

Question 19

What is the optic disc?

Answer 19

Point of CNII formation
Only point of entry/exit for blood vessels and axons of CNII

–> Blind spot

Question 20

Where is the greatest density of cones?

Answer 20

Macula

Question 21

What is the fovea?

Answer 21

Depression in the centre of the macula

Area of most acute vision

Question 22

What is the resulting feature of complete interruption of flow of the central artery or vein?

Answer 22

Monocular blindness

Question 23

Light from objects in the right visual field is processed where in the brain?

Answer 23

Left primary visual cortex

Question 24

Light from objects in the lower visual field is processed where in the brain?

Answer 24

Upper part of the primary visual cortex

Question 25

What are the 7 extra ocular skeletal muscles?

Answer 25

Lateral rectus
Medial rectus
Superior rectus
Inferior rectus

Superior oblique
Inferior oblique

Levator palpabele superioris

Question 26

What does elevator palpable superioris do?

Answer 26

Elevates the superior eyelid

Question 27

Which extra ocular muscle passes through the trochlea?

Answer 27

Superior oblique

Question 28

How are the extra ocular muscles innervated?

Answer 28

LR6 SO4 AO3

• lateral rectus = abducent nerve (CN6)
• superior oblique = trochlear nerve (CN4)
• all others = oculomotor (CN3)

Question 29

Which eye movement in lateral rectus responsible for?

Answer 29

Abduction

Brings line of gaze into same plane as inferior and superior rectus (so they can be tested)

Question 30

Which eye movement is medial rectus responsible for?

Answer 30

Adduction

Brings line of gaze into same plane as inferior and superior oblique attachments

Question 31

How is superior rectus tested?

Answer 31

Abduct eye, then elevate

Question 32

How is inferior rectus tested?

Answer 32

Abduct eye, then depress

Question 33

How is inferior oblique tested?

Answer 33

Adduct eye, then elevate

Question 34

How is superior oblique tested?

Answer 34

Adduct eye, then depress

Question 35

Which structures pass into the orbit via the optic canal?

Answer 35

Optic nerve

Ophthalmic artery

Question 36

Which structures pass into the orbit via the superior orbital fissure?

Answer 36

Cranial nerves 3, 4 and 6

Question 37

What is a blowout fracture?

Answer 37

Fracture of the medial orbital wall and orbital floor

Question 38

What is the name of the muscle which encircles the eye/orbit?

Answer 38

Orbicularis oculi

Question 39

Which nerve supplies orbicularis oculi?

Answer 39

CNVII (facial) - muscle of facial expression

Question 40

Which muscle is responsible for lifting the eyelid?

Answer 40

Levator palpabrae superioris

Question 41

Where is the lacrimal gland located?

Answer 41

Superolateral to eye (just below eyebrow)

Question 42

What is the nerve supply to the lacrimal gland?

Answer 42

Parasympathetic from CNVII

Question 43

Describe the passage of lacrimal fluid once it leaves the lacrimal gland?

Answer 43

Washes medially over eye –> medial angle –> drains through lacrimal puncta –> nasolacrimal duct –> inferior meatus