Ocular Infections

Question 1

What are some of the defense barriers of the eye?

Answer 1

• Mechanical & anatomical barriers - e.g. eyelids, cilia, blink reflex, intact cornea/conjunctiva
• Tight junction of endothelial and epithelial cells - e.g. blood:aqueous and blood:retinal barriers
• Nonspecific antimicrobials in tears - e.g. lactoferrin, lysozyme, antimicrobial peptides

Question 2

What are the normal flora of the eye?

Answer 2

• Conjunctiva - limited to no normal flora
• if present, predominantly gram positive
  
  • ​Staph sp
  • Micrococcus sp
  • Strep sp.
  • Corynebacterium sp
  • Bacillus sp
• Gram neg rarely present - if present, predominately non-enterics
• Internal structures = sterile

Question 3

How do the eyes of dogs and cats differ?

Answer 3

• the cat eye has much less pronounced response to inflammation than dog
• feline cornea slower to show edema
• detection of early stages of ocular dz in cats can be much more challenging
• number of ocular conditions that only occur in cats
• infectious agents differ

Question 4

Describe the clinical presentation of acute anterior uveitis

Answer 4

• pupil constriction
• incr protein/cells in anterior chamber
• low intraocular pressure
• bulbar conjunctival hyperemia
• iridal swelling
• photophobia
• blepharospasm

Question 5

What are some infectious agents that can cause anterior uveitis in cats?

Answer 5

• FIV
• FIP
• FeLV

Question 6

What infectious agents cause anterior uveitis in dogs?

Answer 6

• Brucella canis
• Erhlichia sp
• Lepto sp
• Rickettsia rickettsii
• Blastomyces dermatitidis

Question 7

What infectious agent typically causes blepharitis in dogs? Do cats get this?

Answer 7

• Coagulase-positive Staph sp. and Strep
• Cats rarely get blepharitis

Question 8

What infectious agents cause keratitis in cats? What about in dogs?

Answer 8

• Cats: FIP
• Dogs: Canine adenovirus 1

Question 9

What infectious agents cause chorioretinitis in cats?

Answer 9

• FIV
• FIP
• Cryptococcus neoformans (same as dogs)

Question 10

What infectious agents cause chorioretinitis in dogs?

Answer 10

• Canine distemper virus
• Erhlichia sp
• Rickettsia rickettsii
• Blastomyces dermatitidis
• Cryptococcus neoformans (same as in cats)

Question 11

What infectious agents cause conjunctivitis in cats?

Answer 11

• FHV-1
• Chlamydia (Chlamydophila) felis
• Mycoplasma sp

**all cause pus

Question 12

What infectious agents cause conjunctivitis in dogs?

Answer 12

• Canine distemper virus
• Canine papillomavirus
• Beta-hemolytic Strep sp.
• Coagulase-positive Staph sp.

**cause pus

Question 13

True or False: Ocular infections of the deeper components of the eye are generally due to systemic agents (often viral) and happen more frequently in cats

Answer 13

True; e.g. retinal degeneration/dysplasia/hemorrhage, stromal keratitis, uveal LSA

• only exception is retinal hemorrhage, also happens d/t Rickettsia in dogs

Question 14

Describe the ophthalmic manifestations of systemic diseases in dogs

Answer 14

• Infectious diseases often involve the uveal tract
• present as iridocyclitis, choroiditis, and panunveitis
• Caused by:
  
  • Viruses: distemper, infectious hepatitis
  • Rickettsia: Ehrlichiosis
  • Bacteria: Brucella canis, Borrelia burgdorferi
  • Fungi: Blasto, Coccidiodes, Histo, Crypto, Aspergillus

Question 15

Describe the ophthalmic manifestations of systemic diseases in cats

Answer 15

• Acute and recurrent conjunctivitis - FHV-1 or Chlamydia
• Ulcerative & stromal keratitis, proliferative KCS, opaque dark brown to black plaque on the cornea, adherence of conjunctiva & cornea erosive surfaces to each other, and dry eye syndrome - FHV-1
• Anterior and posterior uveitis, chronic uveitis, retinal detachment, secondary glaucoma - FIP, FIV, FeLV