Ophth - Orbit and eyelids

Question 1

What species have open orbits?

Answer 1

Dogs and cats

Question 2

What species have closed orbits?

Answer 2

Horses and cattle

Question 3

What does having a closed orbit mean?

Answer 3

Space between the zygomatic bone and frontal bone is linked with orbital ligament

Question 4

What are the extra-ocular muscles of the eyes?

Answer 4

4 cardinal rectus muscles
2 oblique muscles
Retractor bulbi

Question 5

Where do all of the extra-ocular muscles attach?

Answer 5

All attached at equator - widest part of eyeball

Question 6

Where do all the extra-ocular muscles meet at the back of the eye?

Answer 6

Annulus of Zinn

Question 7

What cranial nerve innervates the majority of the extra-ocular muscles?

Answer 7

CNIII - oculomotor nerve

Question 8

What are the thee muscles that are innervated by nerves other than CNIII?

Answer 8

Lateral rectus
Dorsal oblique
Retractor bulbi

Question 9

What nerve innervates the dorsal oblique muscle?

Answer 9

CNIV - trochlear

Question 10

What nerve innervates the lateral rectus muscle?

Answer 10

CNVI - abducens

Question 11

What are some examination techniques for examining the eye?

Answer 11

Check the visual axis
Check the position of the eye in the orbit
Size of globe
Retropulsion - can eye move back in the orbit
Inspect oral cavity
Inspect the nasal/sinus cavities

Question 12

What is the name for abnormal protrusion of the eye from the orbit?

Answer 12

Exophthalmos

Question 13

What is the name for abnormal recession of the eye in the orbit?

Answer 13

Enophthalmos

Question 14

What is lagophthalmos?

Answer 14

Incomplete eyelid closure and globe coverage

Question 15

What is the name for deviation of the eyes from the axis so they arent aligned towards the same object?

Answer 15

Strabismus

Question 16

What can cause exophthalmos?

Answer 16

Space occupying lesions
Neoplastic
Inflammatory

Question 17

What are some common causes of space occupying lesions?

Answer 17

Foreign body
Infection from oral cavity
Infection from sino-nasal
Trauma
Haematogenous infection

Question 18

What are some primary neoplasms in the orbit?

Answer 18

Mesenchymal tumours
Epithelial tumours
Orbital meningioma - nerve sheath tumours

Question 19

What are some secondary neoplasms in the orbit?

Answer 19

Lymphoma
Metastasis
From adjacent tissues eg. SCC

Question 20

What is orbital myositis?

Answer 20

Immune mediated disease affecting eye causing bilateral exophthalmos

Question 21

What is it called when the eye pops out of the socket?

Answer 21

Globe proptosis (globe popped-out-is heheh)

Question 22

What should you do if globe proptosis occurs?

Answer 22

Emergency
Must keep eye moist
Check systemic injuries
Supportive care

Question 23

How do you treat proptosis?

Answer 23

Lift lids over globe to replace under GA
Flush conjunctival sac
Roll out lids and place temporary tarsorraphy

Question 24

When should you perform enucleation in proptosis cases?

Answer 24

When globe is ruptures
3 or more extraocular muscles torn
Complete hyphaema - eye full of blood

Question 25

What can cause enophthalmos?

Answer 25

Muscular atrophy Dehydration Reduced orbital fat Ocular pain - retractor bulbi pulls back Breed related - dolichocephalic dogs Horners syndrome

Question 26

What are the signs of horner's syndrome?

Answer 26

Miosos Third eyelid protrusion Enophthalmos Ptosis

Question 27

What is miosis?

Answer 27

Small pupil

Question 28

What is ptosis?

Answer 28

Drooping of the upper eyelid

Question 29

When should you perform enucleation?

Answer 29

Irreversible loss of vision Ongoing pain and discomfort Chronic glaucoma

Question 30

What are the two approaches of performing enucleation?

Answer 30

Transconjunctival - simpler Transpalpebral

Question 31

When should you perform a transpalpebral enucleation?

Answer 31

When there is infection or neoplastic cells on the surface

Question 32

How do you perform a transpalpebral enucleation?

Answer 32

Suture lids Dissect around Dont pull - can affect other eye across chiasm Remove eye Homeostasis

Question 33

What is different about a transconjunctival enucleation?

Answer 33

Lateral canthotomy - widen the palpebral fissure Section extraocular muscles individually

Question 34

What are the main muscles of the eyelid?

Answer 34

Levator palpebrae superioris Orbicularis oculi Medial palpebral ligament

Question 35

What is the structural plate of the eyelid called?

Answer 35

Tarsus

Question 36

What are the glands called that produce the lipid portion of tears?

Answer 36

Meibomian glands

Question 37

What are the functions of the eyelid?

Answer 37

Mechanical protection Produce/spread tear film Part of lacrimal functional unit

Question 38

What is the name for introversion of the eyelid?

Answer 38

Entropion

Question 39

What is the name for excessive eyelid length?

Answer 39

Macroblepharon

Question 40

What is the name for combined entropion and ectropion?

Answer 40

Diamond eye

Question 41

What is the name for hairs of normal skin irritating the eye?

Answer 41

Trichiasis

Question 42

What is the name for when cilia emerge from the meibomian gland and irritate the eye?

Answer 42

Distichiasis

Question 43

What is the name for when the cilia arise from the meibomian gland but protrude through the conjunctiva (inside of the eyelid)?

Answer 43

Ectopic cilia

Question 44

What is the difference between distichiasis and ectopic cilia?

Answer 44

They both grow out of the meibomian gland but Distichiasis is through the meibomian gland orifice on the eyelid margin Whereas ectopic cilia emerge through the palpebral conjunctiva

Question 45

What is the term for when they cant blink properly?

Answer 45

Lagophthalmos

Question 46

What are the 4 parts that make up brachycephalic ocular syndrome?

Answer 46

Macroblepharon Lagophthalmos Medial entropion Reduced corneal sensitivity

Question 47

How do you treat macroblepharon?

Answer 47

Frequent lubrication Surgical correction to reduce palpebral fissure

Question 48

What is the normal eyelid length? What is an oversized lid?

Answer 48

33-35mm - normal 40-50mm - oversized

Question 49

How do you treat diamond eye?

Answer 49

Blepharoplasty - reconstructive surgery to shorten eyelid and stabilise lateral canthus

Question 50

What indicates that an animal has entropion?

Answer 50

The eyelid margin is not visible

Question 51

How do you treat entropion?

Answer 51

Hotz- celsus technique Tacking sutures - in very young, can grow and correct Refer in complex cases

Question 52

What is the hotz-celsus technique?

Answer 52

Insize along parallel to lid as long as the lid inversion Remove a semicircle of skin Undertreatment is better than taking too much

Question 53

What does ectropion cause?

Answer 53

Frequent conjunctivitis - cant spread tear film

Question 54

How do you treat ectropion?

Answer 54

Eyelid shortening - wedge resection

Question 55

How do you treat distichiasis/ectopic cilia?

Answer 55

Check eyelids thoroughly Can pluck but will grow back Permanent surgical removal en bloc - cryosurgery and electrolysis

Question 56

What are the most common eyelid tumours?

Answer 56

Meibomian gland epithelioma Adenoma Adenocarcinoma Melanoma Squamous papilloma

Question 57

When should you surgically remove eyelid tumours? How is it done?

Answer 57

When the mass is <1/3 of the eyelid length Chalazion clamp stabilises the lid Wedge resection Close with figure-8 suture