Equine Opthalmology Flashcards
What is entropium?
How would you treat it?
Eyelids rolled in
-foals
Tx: Drop with xylazine and Ketamine, no heavy sedation Mild form in foal -Saline bleb -Percutaneous sutures: 1) simple interrupted sutures (inverting pattern) 2) mattress sutures (everting) Severe form: -Sx remove skin
What is ectropium?
Eyelid rolls out
Why do you not want to cut skin with scissors?
They have a crushing action, not good for wound margins
What is eye lid coloboma?
Coloboma = gash, defect, cut
- Acquired
- congenital
What crude method can you use to check if the cornea is intact?
Take a picture, if fussy cornea has blemish
How do you treat an eyelid laceration?
Eye lid suturing
-need close margins
What is very important in eye lid suturing?
Need to be very precise and margins close together
- suture conjunctiva first
- want knot away from eye lid margin
What surgical technique is used, when a large portion of the eye lid needs to be incised. Ie: Squamouse cell carcinoma in cow eyelid?
Slide flap technique
- Borow’s triangles
- slide flap up
- simple interrupted
What is the outer most layer of the cornea
Tear film
-macrophages (control infection and the environment there)
What are the different layers of the cornea?
Outermost to inner most: Tear film Corneal epithelium Corneal stroma Descemet’s membrane Endothelium
What is unique to healthy cornea?
Not vascularised
What is the thickest layer of the cornea?
Corneal stroma
- non pigmented
- collagen fibers (arranged in parallel fashion)
How are the collagen fibers in the corneal stroma arranged?
Parallel fashion
What is the most inner layer of the cornea?
Endothelium
-one cell layer thick
Would you see the tear film of the cornea under microscopic view?
No fixation removes it
What are the clinical signs of Keratitis?
1) blepharospasm (blepharo =eyelid, Squinting)
2) Epiphora (tearing)
3) Corneal edema (increased fluid in the stroma)
4) cornea opacity
What is keratitis?
Inflammation of the cornea
What is blepharospasm?
Squinting
Where do you normally see epiphora?
At the medial canthus of the eye
How can you be absolutely sure the tear film of the cornea is intact?
FLuorescein test
When you do a fluroscene stain, what is stained?
The stroma
What is cornea vascularization?
Eye healing itself, bringing in blood vessels
-can be seen with keratitis
Superficial vascularisation
Heavily branched vascularisation pattern
-common with superficial cornea ulcer
Deep vascularization
Single branched, Long corneal vessels
-deep corneal ulcer
How do you apply eye medication in a horse?
- heavy sedation, local block
- upper fornix of the eye
What are some reason a horse might not respond to eye medication?
Corneal ulcer edge:
- infection underneath the epithelium
- antibiotics not working
Or
Corneal fungal infection
-need to identify and culture
When do you use a conjunctival pedicure flap
Gives additional blood supply
- attached to the cornea
- needs to be removed months later
T/F: Stromal infections always stain with fluorescent
False
Stromal infections do not always stain with fluorescence
What is the correct suture placement for a corneal laceration?
- Suture should not penetrate to the inside
- place knot to the side
- cornea must be appositional
- sutures must be exactly opposite
What is a staphyloma, and what does it usually occure from?
How is it treated?
Staphyloma = iris protruding through laceration of cornea
- Occurs from corneal laceration
- looks like a dark portion protruding from the eye
Tx: push Irish back during surgery, place corneal suture
What is endophthalmitis?
Inflammation of the eye + straining of the eye
What is exenteration?
Complete removal of the eye
