CAL: Optho Cases Flashcards
Tx cherry eye?
- surgical repositioning of the gland
Prognosis of cherry eye after tx?
- ^ chance reprolapse
- ^ risk of same thing happening in the other eye!
Is there a breed association with cherry eye?
Yes: Look up
Why may an eye appear yellow?
Build up of protein and WBCs in the AC superimposed over a blue eye will casue it to look yellow
What would you expect to see with anterior uveitis?
aqueous flare, miosis, conjunctival congestion, colour change to eye/iris are all suggestive of intraocular inflammation specifically anterior uveitis/iridocyclitis.
Signs of orbital cellulitis?
exophthalmos, strabismus, protrusion of the third eyelid, mucopurulent ocular discharge
Signs of corneal melanosis? Is it common in the horse?
visible melanin pigment on the cornea; corneal melanosis is actually an uncommon finding in the horse
Is glaucoma ever 1* in the horse?
although this is a possibility it is almost always secondary to anterior uveitis in the horse, not a primary condition
Is KCS common in the horse?
No
Signs of Horner’s syndrome?
miosis is present, enophthalmos; ptosis; or protrusion of the third eyelid
Is it possible to visualise a cataract through the normal eye? What about the lens in general?
it is not possible to accurately assess the lens for cataract through a small pupil, especially a ‘small’ cataract; an attempt should always be made to dilate the pupil for a thorough examination of the lens
- should be dilated to visualise lens too
What test is always indicated with a red eye in all species?
fluorescin (may be looking for 2* trauma related ulcers if not 1*)
What are corneal ulcers in the horse generally due to?
reflux anterior uveitis
- unlike cat and dog
What is the normal IOP of the horse?
can be >25mmHg!
- compare eyes for symmetry
When is occular ultrasound indicated?
- visualising the posterior segment that cannot be seen through a miotic pupil or opaque anterior segment
- retinal detachemnt and lens position well visualised
- quick and non invasive
Is retinal detachment common in the horse?
definitely possibility in association with uvieits
Are STT readings useful in the horse? When may they be low?
no - generally always sufficient tears
- facial n. paralysis may v STT as some PS innervation to lacrimal gland carried here
define chemosis
conjunctival oedema
deifne mydriasis
dilated pupil
Define miosis
constricted pupil
When is conjunctival scraping indicated?
1* conunctival disease
- not 2* conjunctival inflammation
When is corneal scraping indicated?
corneal cytology. Even if a small corneal ulcer is present unless there is evidence that the cornea is infected (stromal infiltrate, deep ulcer) a corneal scraping can potentially damage the ocular surface more than the disease process itself
Is the tear break up test useful in the horse?
No
Which breeds are predisposed to ERU?
(equine recurrent uveitis)
Apaloosa
What are the top 3 causes of ERU?
- immune mediated disease
- Leptospirosis (though not proven)
- Trauma (sharp -> ulcer OR blunt, no ulcer)
What is a common sequalae to ERU?
Lens dislocation
Infectious cause of anterior uveitis in the cat?
Feline herpesvirus
Tx of anterior uveitis in the horse?
- Topical cyclosporine
- Systemic anti-inflammatories
- r/o ulcer before tx with topical corticosteroids - systemic NSAIDs much preferred over corticosteroids
- Atropine (alleviate iridocyclospasm, break down anterior synechiae which may form with chronic or severe uveitis . NB. gut stasis side effects, monitor borborygmi especially in foals)
Can topical antifungal and antibiotics penetrate through the cornea?
No except chloramphenicol
What is ERU the main cause of in horses?
Blindness usually results from secondary cataract, glaucoma, lens luxation or retinal detachment. The prognosis is always guarded.
Potential causes of white opacity in the eye?
- Corneal dystrophy, corneal degeneration and corneal scar (fibrosis) as well as diffuse or focal corneal oedema can all appear as white changes in the cornea. In addition, oedema can appear ‘blue’ and corneal mineralization (lipid or calcium) is often more ‘crystalline’ in appearance. Corneal scars are often smooth and ‘grey’.
- Hypopyon: white blood cells in the anterior chamber, always ventral
- Cataract: focal or diffuse white (or greyish) change in the lens
- Nuclear sclerosis: white or greyish haze (can be quite dense) involving the nucleus of the lens. A common age related change in the dog, can be confused with cataract.
What is iris-atrophy?
Age related change in dogs - moth eaten iris tissue shape
Potential causes of cataract in the dog?
Anterior uveitis, trauma, heritable, age-related, diabetes mellitus and retinal degeneration are all possible and common causes of cataract in the dog.
How do cataracts cause of anterior uveitis?
Leak lens proteins
Common cause of cataracts in dogs? Does this affect cats too?
DM - not cats
- 75% dogs will develop cataract within 1st year of DM, they are bilateral and blinding
- rapidity of development predisposes uveitis
Complications of cataract surgery
Glacuoma, retinal detachment, chronic uveitis
How may age affect success of cataract surgery?
- young dogs ^ fibre growth may -> impaired vision
- old dogs hard lens may be difficult to remove by photoemulsification so ^ risk postop complication
What is important to investigate in young dogs with cataracts?
Persistent hyaloid artery
