Flashcards in 2: eyelids - pearce Deck (67):
what are the components of the eyelid?
- sub Q CT
- orbicularis oculi
- tarsal glands
- tarsal plate
what are the functions of the eyelid?
- tear film production, distribution, and drainage
- oxygen exchange [conjunctiva]
what type of muscle is the orbicularis oculi muscle?
why is its action atypical for similar muscles of this type?
there are medial and lateral ligg, temporal and nasal ligg that modify its sphincter action
what is the function of the orbicularis oculi muscle?
to open and close the eyelids
what is the tarsal plate?
tissue associated w glands that is often very firm
very well developed in humans
what do the tarsal glands produce?
fat and oil - one component of the tear film
what is the palpebral conjunctiva?
the tissue on the inner surface of the eyelid
what does the conjunctiva produce?
specifically, what structure produces this?
the mucus portion of the tear film
prod by goblet cells in the conjunctiva
what are cilia?
what do lacrimal glands produce?
aqueous components of tear film
what is ankyloblepharon?
delayed / incomplete eyelid opening - congenital
often accompanied by mucopurulent discharge
at what age in dogs/cats do the eyes typically open?
10-15 days old
what is the etiology of the mucopurulent discharge associated with ankyloblepharon in dogs?
and in cats?
dogs: Staphylococcus spp
cats: Chlamydophila or FHV-1
what is often the origin of the BacT under the eyelids in puppies and kittens with ankyloblepharon?
a staph infection in the uterus during the pregnancy - causes the eyelids to remain shut
if a client reports their newborns have closed eyes and discharge coming from them, the case can wait until Monday
the case is an emergency - see animals ASAP
tx of ankyloblepharon?
- warm compress with digital pressure
- blunt dissection to help open the eyes - start at medial area of eye b/c the 3rd eyelid is there for a layer of protection during your dissection
careful sharp dissection is appropriate for ankylolepharon
blunt dissection only
what is eyelid agenesis?
what is another name for it?
partial palpebral fissure absence
is eyelid agenesis MC in dogs or cats?
cats - esp wild cats, such as snow leopards
what does eyelid agenesis look like?
normal eyelid margin is not present in some areas along the border of the eyelid - conjunctiva goes directly into the skin in these areas
MC lateral portion of upper eyelid is affected
what are the consequences of eyelid agenesis?
there are exposed areas when the animal blinks - poor protection and lubrication in that area of the eye
- inability to blink normally
- exposure keratitis
- other congenital ocular dzz often accompany this
what is posterior segment coloboma?
holes in the tissue of the posterior segment - often accompanies eyelid agenesis
what are some other congenital ocular dzz that accompany eyelid agenesis?
[she said to look in the text for a more detailed list of dzz that are found with this and this was the only one listed - so idk if its for a test questions or for our own knowledge...]
eyelid agenesis does not always impair vision
may or may not affect vision
one common surgical treatment for eyelid agenesis?
pedicle graft flap, from the lower portion of the lid over the area - delicate sx so should refer this case
what is a choristoma?
normal tissue in an abnormal location
what is a dermoid?
a type of choristoma - specifically a choristoma loc on the eye
many dermoids tend to grow hair
- dep on size, loc, visual impairment
- resection (may be indicated)
- +/- skin or conjunctival grafts
what are 3 common eyelash disorders
what species are they MC in?
MC in dogs
what is trichiasis?
normal hair on the eyelid that contacts the corneal surface
may cause some pigmentation and irritation
relatively benign condition
MC in small white fluffy dogs with fine hair
what is distichiasis?
what does it commonly cause?
a hair follicle starts in the Meibomian gland and extends through the duct of the gland, through the central part if the eyelid margin
usually more sharp hair then in trichiasis
can cause corneal ulcer - definitely corneal irritation
what is ectopic cilia?
what does it commonly cause?
a hair follicle originates the the Meibomian gland and goes through the palpebral surface of the eyelid
very nasty - causes corneal ulcers, pain, epiphora, blepharospasm
often seen in young dogs with UNCER LOC IN CENTRAL UPPER EYELID, DORSAL PART OF CORNEA
what is the typical presentation of a traumatic corneal ulcer?
in the center of the cornea
which eyelash disorder is most common in horses?
- acquired trichiasis, post trauma
what are treatment options for distichia?
electroepilation and cryoepilation
which treatment option for distichia is most conventional and more widely used?
how does cryoepilation work?
what is one consideration to take when using this method?
- used for many distichia
- freeze eyelid on each side - 2 freeze thaw cycles - follicle is killed so hairs may fall out or manually pull them out
- intense swelling and depigmentation of lid margin occurs [temporarily]
- the freezing will inhibit tissue healing so do not perform at the time of other ocular surgery, or if you do, be careful how liberal your margins of freezing re
the purpose of the cryoepilation procedure is to efficiently get rid of all distichia bothering the animal in one procedure
goal is to reduce the load and make the animal more comfortable, not to remove every distichia on the eyelid - patient may need another procedure if there are many distichia
what is the Tx for ectopic cilia?
excision and cryoepilation
what is the Tx for trichiasis?
none if asymptomatic
clip hair short
Sx rarely necessary
what syndromes are part of brachycephalic ocular syndrome?
- macropalpebral fissures
- medial trichiasis
- medial lower lid entropion
- pigmentary keratitis
- nasal trichiasis
tx for brachycephalic ocular syndrome?
medial canthoplasty - for young dogs with excessive corneal exposure and excessive pigmentation
[essentially, is a form of plastic surgery - improves comfort for dog]
- cyclosporin and meds to dec irritation and inc tear production
what is entropion?
conformation eyelid abnormality
what is ectropion?
conformational eyelid abnormality - eyelid eversion
what is lagophthalmos?
inability to completely blink due to conformational eyelid abnormality
MC in brachycephalics
what is combined entropion-ectroption disorder?
"diamond eye" - eyelid is inverted and everted in various locations around eyelid
2* to excessive eyelid length [euryblepharon]
common in bloodhounds, st bernards, clumber spaniel
what are the etiologies of entropion?
- congenital / genetic
what is spastic entropion?
eyelids touch cornea - very painful -> eyelids roll in further -> vicious cycle exacerbated
what is cicatricial entroption?
MC in what species?
fibrosis 2* to chronic spastic entropion -> trauma -> irritation
common in cats [often assoc w herpes infection]
feline entropion in young cats is MC 2* to whaat conditions?
2* to conjunctivitis and corneal ulceration [spastic]
conjunctivitis MC, cicatricial
feline entropion in old cats is due to?
often lose weight so lose fat -> lose orbital volume
feline entropion in Persian cats is due to?
feline entropion in Maine Coone cats is due to?
what is a very important thing to do accurately prior to sx correction of entropion?
get rid of spastic component to measure - add topical anesthetic to eye the measure the tissue with the eye fully open
DO NOT take too much tissue out or you will cause more problems -> do not over correct and you cannot put tissue back in later once you take it out
when is eyelid tacking performed?
after animal is skelatelly mature
if done on puppies, it is temporary
often in Shar pei's
what are entropion tx options?
- get rid of spastic component
- measure skin to take out using calipers
- close using "law of bisection" to ensure good physiologic flap of skin makes the closure clean
what occurs if you over correct during entropion sx?
you cause ectropion
what are principles of repair as per Wedge Resection for simple eyelid lacerations?
- less than 1/3 eyelid margin lost
- 2 layer closure
- margin apposition critical [figure of 8 suture good for good tissue apposition]
what is the 2 layer closure procedure during ectropion correction and eyelid laceration repair?
1. subQ interrupted suture
2. figure 8 suture
3. simple interrupted skin suture
what is blepharitis?
differentials for blepharitis?
infectious [bacT, fungal, parasitic]
immune mediated [allergic or vesicularbullous dzz]
other: solar, foreign body, self trauma
how to work up blepharits?
smear on slide and look at tissue
what is typical of eyelid tumors in dogs?
benign adenomas [80% benign]
what is typical of eyelid tumors in cats and cattle?
what is typical of eyelid tumors in horses?
SCC or sarcoids
plan for dog eyelid tumor?
suspect benign adenoma tumor
cut tumor flush w eyelid - submit for histopath
incise palpebral conjunctiva perpendicular to lid margin
currette to remove tumor and debris
2 freeze and thaw cycles