Equine ophthalmic disease and treatment Flashcards
typical presentation of ulcerative keratitis (corneal ulceration)
usually painful
corneal opacity
secondary uveitis typically present
List 4 things seen with secondary uveitis
myosis
empyema/ hyphema/ synaechiae
iris prolapse
fibrin in anterior chamber
diagnosis of ulcerative keratitis
Fluorescein Stain- Observe with blue light
Management of ulcerative keratitis
does it need debriding
pain management
antimicrobials
NEVER steroids with corneal ulcers
why do we do grid/ puncture keratotomy over an ulcerated eye
Exposes stromal collagen
Promotes epithelial stronger attachment
Takes longer (1-3 weeks) but more likely to heal
List 2 forms of antimicrobial treatment of corneal ulcers
Ointments= more suitable for owner’s administration (3-4 times daily)
Drops= best in hospital settings (from 12 to 4 times daily)
Pain management of corneal ulcers
flunixin meglumine IV - most efficacious
paracetamol
opiods?
topical anti-inflammatories
how to control myosis in corneal ulcers
Topical atropine until mydriasis then as required to maintain
also need- dark environment and mask
List 2 ways to prevent Collagenolysis in corneal ulcers
autologous serum
EDTA plasma
require frequent administration so only suitable for hospital setting
Describe sub-palpebral lavage devices in horses with corneal ulcers
they allow you to lavage the eye without having to open it or get in the horses face
Describe the 2 types of presentation of viral keraitis
Type I – Dendritic pattern
Type II – Multifocal pattern- more common
Describe how to treat viral keratitis
Idoxuridine for 7 days
Can try other anti-virals= e.g. Acyclovir (II), trifluridine (I, II), vidarabine
Treatment of fungal keratitis
azole antifungals
Subconjunctival Amphotericin B
Prophylactic antimicrobials
EDTA, serum, tetracyclines
when should we refer a corneal ulcer
Positive Seidel test (evidence of perforation), iris prolapse
Severe uveitis
Melting
Requires debridement and you are not happy to debride
Deteriorates despite treatment
Horse difficult to medicate
when should you consider enucleation in cases of corneal ulcers
if eye is non-visual
How to treat immuno-mediated keratitis
Dexamethasone
Calcineurin inhibitors (Cyclosporin A and Tacrolimus)
Doxyciclyne
Main thing to do when looking at corneal disease in horses
use stain
if +ve more likely corneal disease- so then do that treatment
if -ve more likely immune mediated- steroids to treat
How to treat eye neoplasia
Mytomycin C- Daily for a week every other week for 4 treatments
Cryotherapy
surgical debridement
enucleation is always an option
what is the uvea
Iris
Ciliary body
Choroid – blood supply to retina
when does equine uveitis occur
secondary (trauma, ulceration, any ocular disease)
primary (immunomediated, equine recurrent uveitits)
what can equine uveitis lead to
Synechiae
Iris rests
Change in iris pigmentation
Reduction in size of corpora nigra
Cataracts
Retinal detachment
Glaucoma
BLINDNESS
Difference between equine uveitis and equine recurrent uveitis
First time? –>Uveitis
More than once –> suspect ERU
what horse breed is predisposed to equine recurrent uveitis
Appaloosas
How to treat equine recurrent uveitis
topical steroids (immune-mediated disorder)
atropine
+/- cyclosporin A
Supra-choroiodal cyclosporine implant- long term managament
what can really help treat equine recurrent uveitis - decribe
Supra-choroiodal cyclosporine implant
needs to be done during remission and cause >5 years remission
can be repeated
How to treat iris cyst
Benign neglect
Can aspirate if a problem- they can rupture
Laser
what signs can iris cyst cause
Can obstruct vision
Head-shaking
Can rupture
Describe habronemiasis - and treatment
granulomatous lesions from flies
ivermectin, systemic NSAIDs and fly control
How to debride corneal ulcers
using a cotton bud, needle, scalpel or bur
why serum eye drops useful for ulcers in horses
the serum has anti-collagenase activity, antibodies within the serum to help fight the infection, nutrients, growth factors and vitamins are present
why is EDTA given in the serum eye drops for corneal ulcers
EDTA helps slow the breakdown of the stroma and give the antibiotics time to clear the infection
what causes viral keratitis
EHV-1,2 and 4
(EHV-2 is the main cause)
Describe how stromal abcesses can occur
if debridement of a corneal ulcer is unsuccssful, the ulcers top layer can heal but leave an abscess in the stroma - this will eventually heal but may take longer
common types of neoplasia in the eye
squamous cell carcinoma
melanomas
