Lacrimal System Flashcards Preview

RUSVM SAM 2 > Lacrimal System > Flashcards

Flashcards in Lacrimal System Deck (24):
1

What glands provide the aqueous layer of the tear film?

Lacrimal gland
Gland of third eyelid

2

How do you diagnose production of aqueous layer?

Superficial corneal and conjunctival inflammation = keratoconjunctivitis

Schirmer tear test I
<15mm wetting/minute = sicca (dry)

3

What are causes of quantitative KCS?

* Immune mediated destruction of lacrimal tissue *

Excision of third eyelid gland

Parasympathetic nerve lesions

Canine distemper

Drugs - atropine and sulfa drugs, anesthetics

4

What breeds are susceptible to KCS?

Small toy breeds

Cocker spaniel
Yorkshire terriers
West highland terrier
Bulldogs

5

T/F: KCS is usually bilateral

True

6

Clinical signs associated with acute KCS?

Mucopurleunt discharge

Blepharitis

Keratitis (superficial corneal neovascualrization) — seen dorsally first as tear film settles to ventral cornea

Conjunctivitis ( conjunctival hyperemia)

7

Chronic clinical signs due to KCS?

Corneal pigmentation

8

Treatment for KCS?

Topical cyclosporine — lifelong therapy

Tcell inhibitor and prevents destruction of lacrimal tissue
Anti-inflammatory effects
Should see response in 4-6weeks

9

What can you try to give a patient for KCS if they are unresponsive to cyclosporine A?

Tacrolimus (ophthalmic)

10

What are the 4 objectives of KCS treatment?

Replace tears (lubricate with artificial tear ointment)

Simulate more tears
Anti inflammatory
(Cyclosporine)

Antibiotic
- clear infection while tear film recovers

11

What is the cause of neurogenic KCS?

Loss of PSNS innervation to lacrimal gland and ispilateral nostril (dry nostril = xeromycteria)

— trauma, otitis interna, neoplasic, idiopathic

12

Treatment for neurogenic KCS?

Pilocarpine. — simulate PSNS
Can be oral or topical

13

What virus causes destruction of lacrimal glandular epithelium leading to KCS?

Canine distemper

Young dogs without proper vaccination (acute and severe)

14

What surgical therapy is used to treat KCS?

Parotid duct transposition
— when medical therapy fails

— parotid salivary duct is moved to lower conjunctival fornix and saliva replaces tears (must feed small and frequent meals)

15

What are disadvantages of parotid duct transposition?

Reaction to higher pH of tears

Moist pyoderma from overproduction

Mineral deposition in cornea and eyelids

16

What produces the lipid layer of the tear film which is important to stabilize the aqueous layer and prevent evaporation?

Meibomian glands

17

If you have clinical signs associated with keratoconjunctivitis but a normal shimmer tear test, what is this likely caused by?

Qualitative keratoconjunctivitis sicca

Check meibomian glands
Or disorders of mucin layer (goblet cells)

18

What clinical signs can be associated with qualitative keratoconjunctivitis sicca?

All KCS — blepharospasm, epiphora, hyperemia, superficial conjunctivitis, and keratitis

Corneal fibrosis — disorganized epithelium and storm create a whitish hazy appearance

19

What is the tear film breakup time test?

The time it takes fluorescin stain to break up on the ocular surface

Normal = 20sec

Abnormal <20sec indicated mucin deficiency

20

Treatment of qualitiative KCS?

Replace tears — lubricate with artificial tears

Reduce inflammation and stimulate tear production — immunomodulation

21

What do you call an overflow of tears on the face?

Epiphora

22

Causes of epiphora?

Poor drainage
— imperforate or hypoplastic puncta
— entropion

Blockage
—foreign body
— inflammation
— neoplasia

23

Diagnostics for epiphora?

Jones test — flurorescin stain in eye, observe in nostril (+ means patency)

Flushing of NL duct
-inert catheter into puncta and look for flow from opposite puncta, then occlude puncta and look for flow out nostril

24

What breeds do you see imperforate punctum? What is the treatment?

Cocker spaniel
Golden
Miniature poodle

Surgical resection and temporary placement of stent with topical antibiotics