Equine ophthalmology 2 Flashcards

1
Q

Describe the treatment of fungal ulcers in horses

A
  • Topical antifungals
  • Miconazole, itraconazole, high strength canesten (cream so stays in eye)
  • May exacerbate uveitis initially due to fungal death
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2
Q

Discuss the use of bandage contact lenses in the treatment of equine ulcers

A
  • Maintain apposition of healing ulcer
  • Reduce pain
  • Protection
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3
Q

What methods of debridement are available for the treatment of equine ulcers

A
  • Cotton swab and local anaesthetic
  • Paint neat iodine onto eye, caustic irritant to set up inflammatory reaction and trigger healing
  • Keratectomy
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4
Q

Explain how debridement with cotton swabs can be used in the treatment of equine ulcers

A
  • Remove inflammatory mediators +/- pathogens
  • Forces edges to come back in
  • Edges must be healthy tissue
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5
Q

Explain the use of neat iodine in the treatment of equine ulcers

A
  • Caustic irritant agent

- Sets up inflammatory reaction and triggers healing

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6
Q

Describe the explain the use of keratectomy in the treatment of equine ulcers

A
  • Needle or grid
  • Usually require anaesthesia, can attempt with standing sedation
  • Sets up inflammatory response that stimulates healing
  • Promotes adherence of epithelium
  • Required for cases that are, or are at risk or becoming indolent
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7
Q

List the surgical options for the treatment of equine ulcers

A
  • Bandage contact lenses
  • Debridement
  • Conjunctival pedical flaps
  • Third eyelid flaps
  • Temporary tarsorrhaphy
  • Amniotic membrane flaps
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8
Q

What are the indications for the use of conjunctival pedical flaps in horses?

A
  • Deep melting ulcers
  • Large superficial ulcers
  • Corneal perforation
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9
Q

Explain the use of conjunctival pedical flaps in the treatment of ulcers in horses

A
  • Maintain for 1-3 months then remove
  • Always some post-op scarring and some vision impairment, but will have peripheral vision and cope well
  • Better ophthalmic surgeon = thinner graft, better result, less visual impairment
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10
Q

Discuss the use of third eyelid flaps in the treatment of equine ulcers (indications, method, considerations)

A
  • Indications: Superficial ulcers, facial paralysis (exposure keratitis)
  • Eyelids sewn together
  • Not as popular as cannot see healing of eye
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11
Q

What is the main disadvantage of temporary tarsorrhaphy?

A

Cannot see healing of the eye

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12
Q

Describe the method, advantages and disadvantages of amniotic membrane flaps in the treatment of equine ulcers

A
  • Amnion sterilised and frozen in small sections, then appplied to surface of cornea
  • Provides no blood supply,
  • But very thin and will be resorbed
  • Provides protection of surface and strength
  • Better cosmetic result than pedical flap
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13
Q

Describe the clinical signs and diagnosis of viral keratitis in horses

A
  • Subtle fluorescein staining
  • Mild corneal oedema
  • Mild pain
  • Staining shows “pinpricks” on cornea
  • Signs intermittent
  • Slit lamp/ophthalmoscope can be useful
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14
Q

Describe the treatment and resolution of viral keratitis in horses

A
  • Topical antivirals e.g. acyclovir, other cyclovirs
  • Topical NSAIDs
  • Tend to resolve without treatment in 3-6 weeks, with treatment in 2-3 weeks
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15
Q

Which virus is commonly implicated in viral keratitis of horses?

A

EHV-2 (but is ubiquitous in environment and may be incidental)

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16
Q

Give examples of strategies for the application of topical eye treatments in horses that resent this

A
  • Solutons sprayed from distance using insulin needle
  • Subpalpberal lavage systems (dorsal fornix application better coverage than ventral fornix application)
  • Nasolacrimal duct catheters (poorly tolerated, rare)
17
Q

Describe the approach to ophthalmic cases in the horse that are resistant to treatment, e.g. indolent ulcers

A
  • Enucleation
  • Can be done standing or GA
  • Implants to preserve cosmetic result if needed (GA)
  • Most horses manage well
  • Chronic uveitis leads to chronic pain, so removal may improve temperament
18
Q

Why may enucleation of the right eye be more significant than the left in the horse?

A

Is the traffic eye, can have significant impact on insurance

19
Q

What are the potential causes of glaucoma in horses?

A
  • Uveitis
  • Congenital
  • Neoplasia (blocking drainage angle)
20
Q

Describe the clinical signs for glaucoma in the horse

A
  • Dilated pupils
  • Corneal band opacities
  • Uveitis
  • Optic nerve atrophy
  • Poor vision
21
Q

Outline the treatment for glaucoma in horses

A
  • Same as for small animals: surgical and medical
  • Prostaglandin analogue eye drop
  • Analgesia
  • Topical carbonic anhydrase inhibitors
  • Adrenergic agents