Eyes

Question 1

What muscle controls the closing of thee eyelid and what innervates it

Answer 1

Orbicularis oculi muscle

Facial nerve

Question 2

What innervates the eyelid closing muscles

Answer 2

Oculomotor, facial nerve and some sympathetic innervation

Question 3

What is the function of the meibomian glands

Answer 3

Produce meibum (lipid part of the tear film)

Question 4

What is the function of the eyelid

Answer 4

• Protects eye from trauma

- Blinking distributes tear film and removes debris from ocular surface

Question 5

What is the function of tear film

Answer 5

Provides nutrition and hydration of the ocular surface

Question 6

What is the function of the nasolacrimal system

Answer 6

Drains tear film

Question 7

Define entropion

Answer 7

Inward turning of all or parts of the eye margin

Question 8

Define Ectropion

Answer 8

Outward turning of the rim of the eyelid

Question 9

List conditions of the cilia

Answer 9

• Distichiasis
• Ectopic cilia
• Trichiasis

Question 10

Define Distichiasis

Answer 10

Extra eyelashes emerging from meibomian gland orifices

Question 11

Define ectopic cilia

Answer 11

Cilia arise from follicle inside or near meibomian gland and emerge through the conjunctiva surface of eyelid

Question 12

Define Trichiasis

Answer 12

Normally located cilia but abnormally directed hair which contact the ocular surface

Question 13

What is the function of the third eyelid

Answer 13

• Protects ocular surface
• Distributes tear film and removes debris
• Contains immunoglobulin secreting plasma cells

Question 14

What are the layers of tear film

Answer 14

Lipid
Aqueous
Mucin

Question 15

Origin of the lipid part of the tear film

Answer 15

Meibomian glands

Question 16

Origin of the aqueous part of tear film

Answer 16

Orbital and nictitans glands

Question 17

Origin of muni part of tear film

Answer 17

Conjunctival goblet cells

Question 18

Function of tear film

Answer 18

-provides nutrients to the ocular surface
-protects the ocular surface from desiccation and bacteria
-lubrictes the ocular surface
Provides smooth transient ocular surface

Question 19

Describe the anatomy of the cornea

Answer 19

• stratified, squamous non-keratinised epithelium
• basement membrane
• collagenous stroma
• Descement’s membrane
• endothelium

Question 20

How is corneal transparency maintained

Answer 20

Low cell density
Relatively dehydrated state
Smooth optical surface
Lacks keratinisation, blood vessels and melanin
Very regular arrangement of collagen fibrils

Question 21

What is keratoconjunctivitis

Answer 21

Dry Eye

Is a local immune mediated destruction of orbital and nictitans lacrimal glands

Question 22

What is a corneal ulcer

Answer 22

Disruption of the corneal epithelium and stroma

Question 23

How do stromal corneal ulcers heal

Answer 23

Healing of the storma starts after cornel epithelium is healed
Fibroblasts migrate in and new collagen is laid down
Vascularisation occurs causing scar tissue to be formed

Question 24

What makes up the anterior uvea

Answer 24

Iris and ciliary body

Question 25

What makes up the posterior uvea

Answer 25

Choroid

Question 26

What is the function of the iris

Answer 26

Controls the amount of light entering the eye and forms part of the blood-ocular barrier

Question 27

What is the function of thee ciliary body

Answer 27

Controls accommodation and produces aqueous humour, anchors lens, makes up part of the blood aqueous barrier

Question 28

Name the 5 layers of the choroid

Answer 28

``` Suprachoroidiae Large vessel layer Medium vessel layer Choriocapillaris Bruch’s membrane ```

Question 29

What is the function of the choroid

Answer 29

Blood supply for retina Part of blood ocular barrier Includes the tapetum

Question 30

What makes up the blood ocular barrier

Answer 30

Blood aqueous Barrier and blood retina barrier

Question 31

What is uveitis

Answer 31

Inflammation of the uvea

Question 32

How is aqueous humour produced

Answer 32

Is produced by the ciliary processes by diffusion, ultrafiltration and active secretion

Question 33

How is aqueous humor drained

Answer 33

By the uveal trabecular mesh work

Question 34

What is a glaucoma

Answer 34

Where increased intraocular pressure results in damage to the retina and optic nerve with loss of vision

Question 35

Describe posterior lens luxation

Answer 35

Is when the lens moves backwards into the eye

Question 36

Describe anterior lens luxation

Answer 36

When the lens moves forward and can block the flow of aqueous humour and can cause secondary glaucoma

Question 37

What causes lens luxation

Answer 37

The zonule fibres weaken and break causing lens luxation

Question 38

What causes the development of cataracts

Answer 38

When the amount of protein in the composition of the lens changes

Question 39

Define exophthalmos

Answer 39

Anterior displacement of the globe (bulging or protruding eyeballs )

Question 40

Define enophthalmos

Answer 40

Posterior displacement of globe

Question 41

Define hydrophthalmos

Answer 41

Congenital glaucoma

Question 42

Define microphthalmos

Answer 42

A severe developmental disorder of the eye which one or both eyes are abnormally small and have atomic malformations

Question 43

Define anisocoria

Answer 43

Unequal pupil size

Question 44

Define miosis

Answer 44

Excessive constriction of the pupil of the eye

Question 45

Define mydriasis

Answer 45

Dilation of the pupil of the eye

Question 46

Define strabismus

Answer 46

Abnormal alignment of the eyes (the condition of having a squint)

Question 47

Define nystagmus

Answer 47

Rapid involuntary movements of the eyes

Question 48

What are the important retinal layers

Answer 48

``` Nerve fibre layer Ganglion cell layer Outer nuclear layer Photoreceptors layer Retinal pigments epithelium ```

Question 49

How many layers make up the retina

Answer 49

10

Question 50

What is the fundus

Answer 50

The portion of the posterior segment of the eye that is viewed with the ophthalmoscope

Question 51

What nerve provides sensory innervation to the eyelids

Answer 51

Trigeminal nerve

Question 52

What tear producing gland is present at e base of the third eyelid

Answer 52

Nictitans gland

Question 53

What is the purpose of the lipid layer of the tear film

Answer 53

Limits evaporation from the surface

Question 54

From where do corneal stem cells originate

Answer 54

Limbus

Question 55

How would you differentiate nuclear sclerosis from a cataract

Answer 55

Distant direct ophthalmology

Question 56

From where does the developing lens (in the foetus) obtain its nutrition

Answer 56

Tunica vasulosa lentis

Question 57

What are the black masses suspended from the edge of the pupil in the horse eye

Answer 57

Corpora nigra