Equine ophthalmology 2 Flashcards
Describe the treatment of fungal ulcers in horses
- Topical antifungals
- Miconazole, itraconazole, high strength canesten (cream so stays in eye)
- May exacerbate uveitis initially due to fungal death
Discuss the use of bandage contact lenses in the treatment of equine ulcers
- Maintain apposition of healing ulcer
- Reduce pain
- Protection
What methods of debridement are available for the treatment of equine ulcers
- Cotton swab and local anaesthetic
- Paint neat iodine onto eye, caustic irritant to set up inflammatory reaction and trigger healing
- Keratectomy
Explain how debridement with cotton swabs can be used in the treatment of equine ulcers
- Remove inflammatory mediators +/- pathogens
- Forces edges to come back in
- Edges must be healthy tissue
Explain the use of neat iodine in the treatment of equine ulcers
- Caustic irritant agent
- Sets up inflammatory reaction and triggers healing
Describe the explain the use of keratectomy in the treatment of equine ulcers
- 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
List the surgical options for the treatment of equine ulcers
- Bandage contact lenses
- Debridement
- Conjunctival pedical flaps
- Third eyelid flaps
- Temporary tarsorrhaphy
- Amniotic membrane flaps
What are the indications for the use of conjunctival pedical flaps in horses?
- Deep melting ulcers
- Large superficial ulcers
- Corneal perforation
Explain the use of conjunctival pedical flaps in the treatment of ulcers in horses
- 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
Discuss the use of third eyelid flaps in the treatment of equine ulcers (indications, method, considerations)
- Indications: Superficial ulcers, facial paralysis (exposure keratitis)
- Eyelids sewn together
- Not as popular as cannot see healing of eye
What is the main disadvantage of temporary tarsorrhaphy?
Cannot see healing of the eye
Describe the method, advantages and disadvantages of amniotic membrane flaps in the treatment of equine ulcers
- 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
Describe the clinical signs and diagnosis of viral keratitis in horses
- Subtle fluorescein staining
- Mild corneal oedema
- Mild pain
- Staining shows “pinpricks” on cornea
- Signs intermittent
- Slit lamp/ophthalmoscope can be useful
Describe the treatment and resolution of viral keratitis in horses
- Topical antivirals e.g. acyclovir, other cyclovirs
- Topical NSAIDs
- Tend to resolve without treatment in 3-6 weeks, with treatment in 2-3 weeks
Which virus is commonly implicated in viral keratitis of horses?
EHV-2 (but is ubiquitous in environment and may be incidental)
Give examples of strategies for the application of topical eye treatments in horses that resent this
- 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)
Describe the approach to ophthalmic cases in the horse that are resistant to treatment, e.g. indolent ulcers
- 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
Why may enucleation of the right eye be more significant than the left in the horse?
Is the traffic eye, can have significant impact on insurance
What are the potential causes of glaucoma in horses?
- Uveitis
- Congenital
- Neoplasia (blocking drainage angle)
Describe the clinical signs for glaucoma in the horse
- Dilated pupils
- Corneal band opacities
- Uveitis
- Optic nerve atrophy
- Poor vision
Outline the treatment for glaucoma in horses
- Same as for small animals: surgical and medical
- Prostaglandin analogue eye drop
- Analgesia
- Topical carbonic anhydrase inhibitors
- Adrenergic agents