Lecture Five: Conjunctiva

- Smooth inner eyelid lining

- Disperse tear film

- Ocular immunologic protection (IgA)

- Produce mucinous portion of tear film (goblet cells)

- Remove debris

What are the 5 functions of the conjunctiva?

Goblet cells of the conjunctiva

What produces the mucinous portion of the tear film?

- Stratified squamous to columnar (NOT keratinized)

- Regionally variable goblet cells

What cells make up the conjunctiva?

- Conjunctival vessels —> most superficial; move, turn at the limbus; blanch with epinephrine

- Episcleral vessels —> attached to the globe; presence indicates intraocular disease

What are the 2 types of vessels you may see on a conjunctival exam?

- Schirmer tear test****

- Culture

- Conjunctival scrape

- Biopsy

What 4 tests can be done for conjunctival diagnostics? Star the one that must be done in every case.

- Dermoid

- Normal tissue in abnormal location

What is a choristoma?

- Dermoid

- Abnormal tissue in normal location

What is a hamartoma?

- Rare in dogs unless a secondary infection

- Cats (due to chlamydia, mycoplasma)

Signalment for bacterial conjunctivitis.

Herpesvirus

distemper

What is a common cause of viral conjunctivitis in cats? dogs?

- Seen in young, stressed cats

- Keratitis

- Hyperemia

- Serous then mucopurulent nasal discharge

- Dendritic corneal ulcers

What signs are seen in viral conjunctivitis due to feline herpesvirus?

- Reduce stress

- L-lysine

- Cidofovir

- Famciclovir

What are the treatment options for viral conjunctivitis in cats due to herpesvirus?

Dendritic corneal ulcer

What is pathognomonic for feline herpesvirus?

Thelazia

What is the most common cause of parasitic conjunctivitis in small animals?

- More common in young dogs

- Rare in cats

What is the signalment for allergic conjunctivitis?

exclusion

allergic conjunctivitis dx?

- May have concurrent atopy, skin disease

- See conjunctival follicles, hyperemia, serous to mucoid discharge

What signs are seen with allergic conjunctivitis?

Topical anti-histamines and/or anti-inflammatories

What is the treatment for allergic conjunctivitis?

• ALWAYS measure Schirmer tear test!

• ALWAYS look everywhere or you will miss it!

• Antibiotics rarely indicated in canine conjunctivitis!

• Steroids rarely indicated in feline conjunctivitis!

conjunctivitis summary

Cow > horse / dog > cat

Conjunctival neoplasia is most common in what species?

must take sample

Conjunctival neoplasia dx?

Excision +/- adjunctive therapy (cryotherapy, radiation, hyperthermia, immunotherapy)

What is the treatment for conjunctival neoplasia?

Hemangioma

What is the most common conjunctival neoplasia in dogs?

Malignant

Is conjunctival melanoma usually benign or malignant?

Sequelae if Tenon's capsule is torn

With conjunctival trauma, why may you see a fat prolapse?

true

TF: Laceration heal quickly, only extensive ones need repaired