Optho Flashcards
What are causes of corneal ulcers?
Trauma, infection, exposure keratitis, tear film deficiency, corneal abrasion due to adnexal disease
What are the classification of ulcers?
1) Acute vs chronic superficial ulcer
2) Mid-stromal ulcer
3) Deep stromal ulcer
4) Descemetocoele
5) Corneal perforation
What is Descemetocele’s membrane?
Last layer of the cornea
Basement membrane of the corneal endothelium
How long does it usually take corneal ulcers to heal?
7-10 days
What are causes of delayed corneal ulcer healing?
Corneal infection, unresolved source of corneal abrasion (distichia, ectopic cilia, entropion, foreign body), KCS, exposure keratitis, neurotrophic keratitis, SCCED (boxer ulcer, indolent ulcer)
What are primary infectious ulcers caused by?
Herpesvirus in cats
What do secondary infections in ulcers cause?
Secondary bacterial or fungal infection will impair healing results in progressive destruction of corneal stroma, causing increasing size and depth of ulcer
What is entropion? What causes it?
Eyelids rolling inward causing hairs to abrade cornea
Causes: conformational and spastic entropion
What is Distichia?
Single or multiple abnormal hairs protruding from meibomian gland opening of eyelids
What is Ectopic Cilia?
Abnormal hairs protruding through conjunctival surface of eyelid
Most common in young dogs, toy breed dogs most commonly affected
Always symptomatic
Big breeds - almost always bulldogs
What is KCS (keratoconjunctivitis Sicca)?
Dry eye
Common cause of corneal ulcers and delayed healing in dogs (rare in cats)
CS - copious mucopurlent ocular discharge
What is exposure keratitis caused by?
Conformational exophthalmos, inability to blink due to facial paralysis, exophthalmos due to orbital disease, buphthalmos due to glaucoma
What causes Neurotrophic keratitis?
Loss of corneal sensation results in spontaneous non-healing ulceration (ophthalmic branch of trigeminal nerve)
What is SCCED? (Spontaneous chronic corneal epithelial defect)?
Characterized by a chronic non-healing superficial corneal ulcer for which no underlying cause can be determined. Middle age dogs most commonly affected.
Also known as boxer ulcer, indolent ulcer, refractory ulcer, recurrent erosion
What are the goals of medical therapy of corneal ulcers?
Prevent/control infection, prevent/control collagenolysis (enzymes break down corneal stroma and cause it to slough off), increase patient comfort, promote corneal healing
