Eyelid disease Flashcards
What is avg length of palpebral fissure in med to large breed dogs?
33 mm
What muscle closes the lids?
Orbicularis oculi
What direction is lid closure? Why?
Lateral to medial; pushes tears to lacrimal puncta
What muscles open the upper lid? (list 3)
- Levator palpebrae
- Müller’s muscle
- Other superficial facial muscles
What muscle opens the lower lid?
Malaris muscle
What is another name for Müller’s muscle
levator anguli oculi medialis
How does the location of the eyelashes in dogs differ from people?
People, it is on the edge of the free margin. Dogs, it’s actually on the outer part of the lid, about 1 mm from the free margin in the upper lid and 2mm from the free margin on the lower lid
How many rows of cilia are there usually in dogs?
2-4
Where do meibomian glands open up?
In the edge of the free margin, in a fine groove
What is the groove that the meibomian glands open up into?
The “gray line”
Why is the “gray line” important?
Used as a surgical landmark to reappose lid margins
If you aren’t sure where the “gray line” is, what can you do?
Squeeze with forceps to get sebaceous material
Where can you see the meibomian glands, and what do they look like?
On the conjunctival surface of the lid
3-4 mm long, white-yellow lines perpendicular to the margin
Where are the glands of Zeis and Moll?
Just outside (in the direction of the lashes) of the gray line
What are the glands of Zeis and Moll?
Modified sweat glands (make lipid)
What is the purpose of the lipid layer made by the glands of Zeis and Moll?
- Prevent tears from flowing onto the lid
2. Helps prevent evaporation of the tears
How does the tarsal plate differ in the dog from a human?
It is thinner, and more flexible and fibrous
What does the tarsal plate do?
Provide site of attachment for muscles
Where is the lacrimal caruncle?
Medial canthus
What is different in the last 2-3 mm of the lids at the lateral canthus? (2 things)
No tarsal plate
No meibomian glands
Sensation to the lids:
Lateral 2/3 of upper lid?
Medial 1/3 of upper lid?
Lower lid?
Lateral 2/3 of upper lid: multiple branches of trigeminal
Medial 1/3 of upper lid: just the ophthalmic br of trigeminal
Lower lid: Maxillary br of trigeminal
What is the primary nerve that provides motor function to the lids? (be specific– name the branch)
Palpebral br of the facial nerve
What are the TWO muscles the facial nerve doesn’t innervate in the eyelids? What does innervate that muscle?
- levator palpebral superioris muscle
2. levator anguli oculi medialis
What innervates the levator palpebral superioris muscle
oculomotor (III) cranial nerve
What innervates the levator anguli oculi medialis?
Sympathetic nerve fibers
What happens if the levator anguli oculi medalis loses innervation?
ptosis of the medial upper lid
Where does lymphatic drainage of the lids converge?
Medial and lateral canthi
What TWO lymph nodes drains the lids? Why is this important?
Parotid ln and mandibular ln
Examine BOTH if there is neoplasia on the lid
Why does physiologic ankyloblepharon exist? (what happens if they open prematurely?)
Immaturity of ocular and adnexal tissues
If opens early, see exposure keratoconjunctivitis, severe ulceration, uveitis, possible perforation
When does the tissue between the lids of a puppy or kitten regress?
10-14 days
If the palpebral fissure opens super early (like a couple days after birth), what probably needs to be done?
Temporary tarsorrhaphy with adjustable sutures
If the palpebral fissure opens early, but not super early, what should be done?
Topical lubricants
What bacteria usually affects the eyes in ophthalmia neonatorum?
Staphylococcus
What is a possible cause for ophthalmia neonatorum?
Genital infection, which contaminates the puppy via the fissure at the medial canthus
What happens if ophthalmia neonatorum is not quickly treated?
There can be irreversible damage to the lacrimal gland, cornea, or entire globe
How do you open the eyelids if there is ophthalmia neonatorum?
Try gently massaging first;
if that doesn’t work, try spreading with mosquitos starting at opening at medial canthus;
if that doesn’t work may need to use scalpel to carefully incise at the medial canthus, then use Steven’s scissors to open the remainder at the line of separation
Eyelid aplasia in DOGS– location most common?
Lateral and LOWER lid
How do dogs with eyelid aplasia usually appear at birth?
Have lid partially or completely open even when neonates
What is one mild form of eyelid aplasia?
Normal lid margin but no meibomian glands
Where are dermoids most likely to be found?
Lower lid, near lateral canthus (disrupts the eyelid margin and is continuous with conjunctiva)
Why are dermoids bad
Hair usually grows toward cornea, and blinking is abnormal
What 3 dog breeds are genetically predisposed to dermoid?
GSD
St. Bernard
Dalmatian
Why do distichia develop from meibomian glands? (vs say, all those other glands)
Meibomian glands are modified hair follicles, and distichia develop from undifferentiated gland tissue
What is the issue with distichia? (2)
- Injury/pain to cornea (if stiff)… obviously
2. Can have a wicking action = overflow of tears over the lower lid margin (moistens margin and exterior aspect of lid)
What breeds are most commonly affected by distichiasis?
- American (69%!) and English (49%) Cocker Spaniel
- Welsh Springer (48%) Spaniel
- Cavalier King Charles (24%)
- Flat Coated Retriever (31%)
- Boxer, English Bulldog, Shetland Sheepdog (25%)
- Shih Tzu, Pek, Tibetan Terrier, Doxie, Poodle, Jack Russel
Is there a relationship with distichiasis and ectopic cilia?
Yes– more prone to having topic cilia
Where else can you get distichia?
The openings for the glands of Zeis or Moll (… so any of these glands)
If you are having trouble seeing/determining if the hairs are distichia, what is one additional feature you can look for?
Mucin adhering to hairs (although sometimes mucin can hide them)
What are the 2 DDx for signs seen with distichia? (superficial keratitis, blepharospasm, mild conjunctivitis, excessive lacrimation)
Trichiasis and entropion
How often is manual epilation needed for distichia?
q4-5 wks
What is the benefits of manual epilation of distichia?
- Owners can do it
- Can confirm clinical signs are d/t distichia and not something else
- No anesthesia
What dogs/breeds are at increased risk of ectopic cilia?
All the same breeds with distichia, and any other dog that you examine that has distichia
What should you look for when examining for an ectopic cilia?
Pigmented conjunctiva around the hair
Where (lid, and specific location) do you usually find ectopic cilia?
Upper lid, 4mm behind lid margin
What breed is more likely to get bundles of ectopic cilia?
Shh Tzu
What breed is more likely to get knots of ectopic cilia?
Poodle (surprise!)
What does the associated corneal ulcer look like when a dog has an ectopic cilia?
Round, superficial defect, without undermined edges, and with vessels
Breeding animal with ectopic cilia. OK to breed?
No, especially if in a breed that is normally NOT affected
When is entropion considered mild, moderate, and severe?
Mild: tilted up to 45 deg
Mod: tilted up to 90 deg
Severe: tilted up to 180 deg
3 causes of secondary entropion?
- Spastic
- Cicatricial
- Loss of lid support (phthisis bulbi, microphtalmos, muscle atrophy, retrobulbar fat resorption)
What 4 breeds most commonly have entire lower lid entropion?
- Rottie
- Chow
- Shar Pei
- Bouvier des Flandres
Those breeds with entire lower lid entropion usually have what wrong with the issue?
Fissure is relatively short
Hunting breeds with entropion usually have what part involved?
Lower lid, lateral 3/4
Giant breeds with entropion usually have what part involved?
Lower lid, lateral half; and lateral canthus
What large/giant breeds are associated with entropion? (3)
GD, St. Bernard, Leonburger
Large/giant breeds with entropion usually have what wrong with their lids that leads to entropion?
Large palpebral fissure
What breeds have upper lid entropion?
Chow and Shar Pei (upper and lower for them!), Basset and Blood hound, Old English Cocker
Why do those specific breeds have upper lid entropion?
Loose circum orbital skin, loose facial folds, heavy ears
What breeds are associated with medial entropion?
Pug, Pek, Poodle (mini and toy), Shih Tzu, CKCS, Bulldog
What breeds tend to have earlier onset to their entropion, and when (age) does it occur?
2-6 wks in Shar Pei and Chow
In the majority of breeds, when (age) do you first see entropion?
4-7 months
How does entropion result in a vicious cycle?
Pain–>enophthalmos–>loss of support of lid margin–>worsening entropion
If you are unsure if there is entropion, what test can you do?
Pinch skin of lid ~10mm from margin, so lid inverts to cornea– should correct in 1 blink, if not then it is habitual entropion
