Ophthalmology: Cats, Rabbits Flashcards
What third eyelid abnormalities can affect feline?
- Retraction of the globe with pain
- Retro-bulbar swellings
- Horner’s syndrome
- Symblepharon
- Lymphoma infiltration
- Systemic malaise and dehydration
What can cause conjunctivitis in cats?
- Herpes virus
- Chlamydophila
- Symblepharon
How is feline herpes treated?
- Famcyclovir and ganciclovir
How is chlamydophila in cats treated?
- Mat be respiratory tract infection or conjunctivitis alone
- Oral doxycycline without topical treatment
What is symblepharon?
How can it be treated?
Permanent adhesion of conjunctival surfaces following inflammation
Correction is surgical- not straightforward- leave alone
What is corneal sequestrum?
- Following a non-healing ulcer a black plaque can develop in the exposed stroma
- Sequestered necrotic corneal stroma
Surgery to remove
How does eosinophilic keratitis appear in cats?
How is it treated?
- A proliferative pale pink irregular mass of inflammatory tissue advances across the cornea
- Often with a thick white discharge
Tx- Topical steroids
- Where does herpes remain dormant in cats?
- What eye lesions can it cause?
- How can it be treated?
- Trigeminal ganglion
- Ulcerative keratitis without conjunctivitis
- Debridement and lubrication may be successful- anti-virals can be used with little data
- Where does herpes remain dormant in cats?
- What eye lesions can it cause?
- How can it be treated?
- Trigeminal ganglion
- Ulcerative keratitis without conjunctivitis
- Debridement and lubrication may be successful- anti-virals can be used with little data
- Where does herpes remain dormant in cats?
- What eye lesions can it cause?
- How can it be treated?
- Trigeminal ganglion
- Ulcerative keratitis without conjunctivitis
- Debridement and lubrication may be successful- anti-virals can be used with little data
What eye problem is frequently a common component of systemic disease- FeLV, FIV, FIP
Anterior uveitis
How does anterior uveitis present differently with the following diseases?
* FeLV
* FIP
* Toxoplasma
* Lymphoplasmacytic
* Uveal neoplasia
FeLV
* Causes typical anterior uveitis
* Possible segment inflammation and retinal detachment
FIP
* May be indistingushable from other causes- large amounts of fibrinout material in the AC
Toxoplasma
* More commonly causes retinitis possibly with anterior involvement
Lymphoplasmacytic
* Most common form- chronic uveitis with grey lymphoid nodules in the iris- potentially glaucoma- steroids in early stages
Neoplasia- melanoma most common
What causes glaucoma in cats?
- Primary does not occur
- Due to obstruction of the drainage angle from acute or chronic uveitis
What more commonly causes lens luxation in cats?
Lymphoplasmacytic uveitis
Describe the fundus of the cat?
- Bright tapetum
- Yellow-green
- Circular disc
- Vessels do not anastomose on the surface of the disc
- What breeds are predisposed to generalised retinal atrophy?
- How does it appear?
- Siamese and Abyssinian
- Extreme hypereflectivity and vascular attenuation- progresses to complete blindness
What systemic diseases can cause retinal detachment in cats?
- FIP
- FeLV
- Hypertension
What needs to be avoided with use of enrofloxacin (baytril)?
Excessive doses can cause sudden irreversible blindness in cats due to toxic damage
When enuceating a cats eye why is excessive traction very bad?
Can damage the opposite optic nerve at the chiasm
What should standard medical treatment be for corneal lacerations and penetrations?
- Mydriatic usually atropine or tropicamide
- Topical broad spec ABs
- Oral broad spec ABs
In larger wounds with iris prolapse, non-viable excised and replaces and sutured
- What shape is rabbits third eyelid?
- How many tear duct openings are there?
- Where is the optic disc?
- Where are retinal blood vessels seen?
- What test is difficult in rabbits?
- Triangular
- Single tear duct opening
- High and dorsal- large depression
- Myelinated fibres extend medially and laterals- BVs present in this region
- Menace response- weak or nil
- What agent commonly causes tear duct infection in rabbits?
- How does it present?
- How can infection be more complicated?
- How can it be treated?
- pasturella spp
- Chronic ocular discharge and secondary corneal infection
- Nasolacrimal duct is near teeth roots- displacement of elongation of the roots- chronic inflammation
- Flushed with povidone:iodine, topical and systemic ABs- regular flushing
Control rather then cure
What may protrusion of the eye and exposure keratitis suggest in rabbits?
Orbital abscess
Difficult to evacuate
What is conjunctival membrane in rabbits?
- When the conjunctiva from the limbus grows over the cornea in a centripetal manner
- Gives the impression that the cornea is vascularised and opaque
Cause unknown- can surgically excise
What is conjunctival membrane in rabbits?
- When the conjunctiva from the limbus grows over the cornea in a centripetal manner
- Gives the impression that the cornea is vascularised and opaque
Cause unknown- can surgically excise
- What is encephalitzoon cuniculi?
- What does it cause in rabits?
- How does it affect the eye?
- Protozoan parasite
- Nervous (head tilt), paresis, paralysis, tremors, convulsions, renal failure
- Enters the lens- rupture, chronic reaction
* Large solid yellow mass- tumour like
* Within or underlying iris
How is E cuniculi abscessation treated?
- Potentially fenbendazole
- Phakoemulsification
Can result in enucleation
What needs to be avoided in enucleation of rabbits eyes?
Rupture of large venous sinuses in the orbit
* Profuse and life threatening haemorrhage
* If happens- section all remaining attachments and remove the eye with max speed
* Suture with continuous subcut suture
