Eyelid and Third Eyelid

Question 1

4 layers of the eyelids

Answer 1

from outside to inside:

skin, muscle, tarsus and meibomian glands, conjunctiva

Question 2

clinically relevant eyelid muscles

Answer 2

orbicularis oculi

levator palpbrae superioris

Muller’s muscle

Question 3

dysfunction of the orbicularis oculi muscle will cause ________

Answer 3

lagophthalmos - incomplete eyelid closure and globe coverage

Question 4

dysfunction of levator palpebrae superioris and muller’s muscle will cause ________

Answer 4

ptosis - drooping of the eyelids (most often upper eyelid)

Question 5

what is the tarsus (tarsal plate)

Answer 5

fibrous and glandular layer of the eyelid

holding layer for eyelid closure, supports meibomian glands

Question 6

T/F the palpebral conjunctiva is often slighly hyperemic relative to the bulbar conjunctiva

Answer 6

True

Question 7

eyelid conformation and eyelid margin abnormalities

Answer 7

entropion

ectropion

lagopthalmos

abnormalities in innervation

abnormal hairs

eyelid tumors

Question 8

entropion

Answer 8

rolling of the eyelid margin such that hairs are touching the ocular surface

key concept: this is an abnormal relationship of the eye in relation to the eyelids

Question 9

anatomic entropion

Answer 9

eyelids not appropriately conformed to eye

unrelated to ocular pain

Question 10

blepharospasm associated entropion

Answer 10

ocular pain stimulates active globe retraction and an altered eyelid to eye relationship

Question 11

bleptharospasm

Answer 11

spasm of the orbicularis oculi muscle resulting in eyelid closure

aka squinting

Question 12

hereditary causes of anatomic entropion

Answer 12

abnormal canthus - brachycephalic

abnormal palpebral fissue - hounds and giant breeds

escessive facial folds - shar pei

Question 13

T/F permanent correction of hereditary anatomic entropion may not be necessary

Answer 13

True

dogs can “grow into their faces”; permanent correction may not be necessary until 6-9 months of age

Question 14

causes aquired causes of anatomic entropion

Answer 14

enophthalmos

blepharospasm that alters anatomy - chronic corneal ulceration, dry eye, conjunctivits

Question 15

Why do we care to differentiate anatomic and blepharospastic components?

Answer 15

Failure to assess the spastic component can lead to over correction and ectropion

Question 16

how can we differentiate anatomic and blepharospasm entropion

Answer 16

take away the ocular pain that induces blepharospasm

proparacaine

Question 17

temporary correction of entropion

Answer 17

viscous lubrication

eyelid tacking

partial temorary tarsorrhaphy

Question 18

permanent correction of entropion

Answer 18

modified hotz-celsus - rolls out the eyelid

Question 19

ectropion

Answer 19

eversion or rolling out of the eyelid

Question 20

common causes of ectropion

Answer 20

iatrogenic - too agressive with entropion correction

hereidary - hounds and giant breeds (often in conjunction with entropion)

Question 21

4 common causes of lagophthalmos (incomplete eyelid closure and globe coverage)

Answer 21

breed variation

exopthalmos

bupthalmos

CN V or CN VII dysfunction

Question 22

secondary eye exposure from lagopthalmos will cause ______

Answer 22

keratoconjunctivitis

Question 23

which nerves are afftected with an abnormal palpebral reflex

Answer 23

CN V (maxillary and opthalmic - sensory) and CN VII (somatic efferent)

Question 24

which nerves are affected with ptosis

Answer 24

CN III or sympathetic pathway lesion (commonly a feature of Horner’s syndrome)

Question 25

Clinical signs of Horner's syndrome are due to disruption of which 3 target sites of the SNS

Answer 25

upper eyelid - muller's muscle iris - iris dilator periorbital cone - circumferential smooth muscles

Question 26

common causes of horners syndrome

Answer 26

otitis nasopharyngeal polyps iatrogenic idiopathic

Question 27

how can horners syndrome be diagnosed

Answer 27

dilute phenylephrine - post ganglionic horners should partially or completely resolve in \<15 min

Question 28

trichiasis

Answer 28

hairs growing from naormal skin reach the cornea and/or conjunctival surface

Question 29

trichiasis commonly effects which breeds

Answer 29

brachycephalic

Question 30

distichia

Answer 30

cilia which emerge from meibomian glands

Question 31

which abnormal hair disorders are treated with cryotherapy

Answer 31

distichia ectopic cilia

Question 32

ectopic cilia

Answer 32

hair/cilia protruding through palpebral conjunctiva

Question 33

T/F eyelid tumors in dogs are typcally malignant where as feline eyelid tumors are typically benign

Answer 33

**False** *canine tumors are typically benign and feline tumors are typically malignant*

Question 34

what should be considered with surgical removal of eyelid tumors

Answer 34

irritation of the ocular surface size location

Question 35

treatment options for canine eyelid tumors

Answer 35

debulk and cryotherapy complete excision

Question 36

4 key concepts for closure of eyelid margin defects

Answer 36

limited debridement closure must be perfect avoid full thickness suture bites tarsus is the holding layer

Question 37

what suture pattern should be used to close eyelid margin defects

Answer 37

figure of 8

Question 38

prolapsed gland of the third eyelid (cherry eye) can lead to ______ if left untreated

Answer 38

chronic conjunctivitis KCS

Question 39

T/F excisions of the gland is an appropriate therapy for cherry eye

Answer 39

**False** *contributes 35-45% of aqueous tear film, exception: third eyelid neoplasia*

Question 40

2 common techniques for treating cherry eye

Answer 40

morgan pocket technique orbital tracking