Equine Ophthalmology Flashcards Preview

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Flashcards in Equine Ophthalmology Deck (29)
1

Give some clinical signs of ulcerative keratitis

-Bleparospasm
-Pain
-Epiphora (excessive eye-watering)
-Photophobia

2

What other stain can you use on the eye to check for ulcers?

Rose bengal

3

Which part of the cornea is damaged with superficial ulcers?

Only the epithelium

4

How do you treat a superficial ulcer?

-Topical antimicrobials +/- topical atropine
-Healing rate= 0.6mm/day

5

Which part of the cornea is damaged with deeper ulcers?

-Stroma
-Scarring likely

6

What is keratomalacia?

Melting ulcer

7

What causes a melting ulcer?

Activation and/or production of proteolytic enzymes by:
-Corneal epithelial cells
-Leucocytes
-Microbial organisms (Pseudomonas)

8

Which bacteria is likely to be in an eye with a melting ulcer?

Pseudomonas

9

How do you treat keratomalacia (melting ulcers) and descemetoceles?

-Topical serum
-Topical EDTA
-Topical acetylcysteine
-Topical tetracyclines or doxycycline
-Systemic NSAIDs eg flunixin

10

What is a descemetacele?

-Melting ulcer that penetrates down to the Descemets membrane
-Will be fluoroscein-negative

11

How do you treat a stromal abscess?

-Antimicrobials (eg fluoroquinalones)
-May need surgery (debridement or corneal grafting)

12

What causes viral keratitis?

EHV-2

13

How would you recognise viral keratitis?

-Multiple superficial, white, punctate or linear opacities
-Varying degree of ocular pain

14

How do you diagnose viral keratitis?

Difficult: virus isolation +/- PCR

15

How do you treat viral keratitis?

-Topical aciclovir
-Topical idoxuridine
-Topical Trifluorothymidine
-Topical Aciclovir
-Topical Interferon γ
-Topical corticosteroid?

16

Are immune-mediated keratopathies usually unilateral or bilateral?

Unilateral

17

How do you treat an immune-mediated keratopathy?

-Medical: topical corticosteroid, cyclosporine A, doxycycline
-Surgical: keratectomy, cyclosporine A implant

18

What can happen if uveitis is left untreated?

Blindness

19

What are the 2 ways anterior uveitis can occur?

-Primary (ie eye trauma)
-Secondary to systemic disease (eg Rhodococcus, Leptospira)

20

Give the clinical signs of anterior uveitis

-Pain: blepharospasm and epiphora
-Chemosis
-Constricted pupil
-Aqueous flare (milky appearance of anterior chamber)
-Blood, pus or fibrin in anterior chamber)

21

How do you treat uveitis?

-Topical corticosteroids (if no ulcer)
-Topical atropine (q 4 hours until pupil dilates)
-Topical NSAID (if ulcer)
-Topical antimicrobial? (if ulcer)
-Systemic NSAID (flunixin)
-Surgery: cyclosporine A implant, enucleation?

22

Give some long-term complications of uveitis

-Atrophy granula iridica
-Synechiae
-Cataracts
-Glaucoma
-Retinal pathology
-Blindness
-Phthisis bulbi

23

'Butterfly' lesions around the optic disc are associated with which condition?

Uveitis

24

What is the normal intraocular pressure of a horse?

15-30 mmHg

25

Give some clinical signs of glaucoma

-Hydrophthalmos/buphthalmos
-Corneal oedema
-Corneal striae
-Lens luxation
-Blindness

26

How do you medically treat glaucoma?

-Carbonic anhydrase inhibitors: topical (dorzolamide) and/or systemic (acetazolamide)
-Topical beta blockers: timolol
-Anti-inflammatories: NSAIDs and/or corticosteroids, topical and/or systemic

27

How do you surgically treat glaucoma?

-Laser destruction of ciliary body
-Aqueous shunts
-Enucleation

28

95% of the retinal blood supply is provided by what?

Choroid vessels

29

Why should you be careful when using atropine?

Can cause gut stasis -> colic