Ophtho 1 & 2 Flashcards
90% of thickness of eye
Is made up by the stroma
Lamellar collagen arrangement
400-800um thick in dogs/cats
Avascular, clarity is critical to function
Optical clarity maintained by
Non-keratinized epithelium
Regular stromal collagen arrangements
Small diameter collagen fibrils
Lack of BV
Relative dehydration
Pre-corneal tear film
4 pathologic corneal diseases
Edema
Vacularization
Pigmentation - species dependent
Scarring/fibrosis
Congenital corneal disorders
Dermoid
Persistent pupillary membranes
PPMs
Embryologic structure that nurses the eye
Strands of tissue, that cause localized edema
Corneal ulceration
Full thickness of epithelium
Clinical signs for corneal ulceration
Blinking/squinting
Localized corneal edema
Conjunctival hyperemia/chemosis
Variable ocular discharge
causes for corneal edema
Trauma** (exogenous vs endogenous)
KCS
Prolonged corneal exposures (FN paralysis, exopthalmos)
Primary infections - FHV1, EHV2, CHV, m.bovis
Endogenous sources of corneal trauma
Entropion - enrolling on the lid
Ectopic cilia - conformational, eyelash on lense
Distichia - hairs outside the eyelid margin
Nasal fold trichiasis - folds near nose rub on eyes
Corneal healing - epithelial
Epithelial sliding and mitosis - quicker healing
Corneal healing - stromal defect
More damage or secondary
Epithelial healing+ keratocyte proliforation and collagen deposit
Will result in a cloudy scar
Normal corneal healing
Quickly, 7-10 days often quicker
Anything past that = something else is wrong
Specific causes for delayed corneal healing
Corneal infection
Unresolved source of corneal abrasion
KCS
Exposure keratitis
Neurotrophic keratitis
SCCED - boxer ulcer
Risk factors for ulcer progression
Tear production normal ?
Can & does the animal blink normally?
Brachycephalic breed/conformational exophthalmos
Adnexal abnormalities
Does ulcer appear infected
Corneal ulceration complications
Secondary infections**
Stromal collagenolysis
Uveitis
Corneal perforation
Descriptive classification of corneal ulcers
Superifical
Stromal
- mid Stromal
- deep stromal
Desemetocele
Diagnostic for eye
Search for underlying cause
Schirmer tear test
Corneal culture
Corneal cytology
Florescein stain
Goals of therapy
Prevent/control infection
Prevent/control collagenolysis
Increase patient comfort
Promote health
Types of medical therapy for corneal ulceration
Antimicrobials - topical
Anti proteolytic agents
- topical autogenous serum
- topical n-acetylcysteine
- systemic tetracyclines
Other medical therapy types
Cycloplegic agents - topical atropine
Other - analgesia, e-collar
Duration for medical therapy
As long as it takes for the epithelium to cover and protect the lesion - tested with fluorescence stain, negative uptake
Topical steroids
Contraindicated use in presence of corneal ulcers
Can inhibit healing, can prolong ulcers
Surgical therapy
SCCED - chronic corneal ulcers
Progressive corneal ulceration
Deep stromal ulcers/descemetocoele
Keratomalacia - melting ulcers
Types of surgical therapy
Keratectomy - removal of necrotic/infected corneal
Corneal/biomaterial graft - structural support
Conjunctival flap/graft - speeds healing of cornea
3rd eye lip flap XX do not use for healing
Conjunctival flaps
Mechanical support
Immediate blood supply
Source of fibroblasts
Source of epithelial cells
SCCED
Spontaneous chronic corneal epithelial defect
*boxer ulcer
Superficial, non healing ulceration
Non-infected
Loose epithelial lip surrounding ulcer
Variable vascularization
Variable pain/discomfort
Treatment for SCCED
Debride the cornea
Keratotomy/tectomy
Manage superficial ulcer till healed
FHV1 keratitis
Corneal ulceration
Dendritic ulcers/erosions
Classic early lesion, rose bengal staining- highlights epithelial ulcers better than florescence
Superficial ulceration/stromal ulceration
other FHV corneal conditions
Stromal keratitis, corneal sequestrum, eosinophilic keratitis
FHV keratitis treatment
Topical antibiotics if ulceration present
Antiviral (topical/oral)**
Anti inflammatories (topical NSAIDS)
Canine herpes virus
Not super common
Ubiquitous infections
Dendritic ulcers or non ulcerative inflammatory DS
Infectious bovine keratoconjuctivitis
Pink eye
Spread by moraxella bovis
Highly contagious - direct contact & mechanical vectors
Etiopathalogic factors for IBK
Bacteria related - pili, cytotoxin
Co- infections
Host related - genetics, age, immunity, stress/nutrition
Environmental - UV exposure, dry/dusty enviro
Ocular lesion of IBK
Corneal ulcer - can progress to rupture
Conjunctivitis, blepharospasm, photophobia, epiphora, mucopurulent discharge
Preventing IBK
No good vaccine
Environmental control is best
Parenteral antibiotics
Subconjuncival antibiotics*
Topical antibiotics
Corneal foreign body
Removal is mandatory
- caution w potential perforation
- surgical intervention in select cases
Topical antibiotics until healed
Corneal laceration/perforation
Partial thickness - Medical management if superficial
(<50% corneal thickness)
Full thickness - surgical intervention probably
Non ulcerative corneal disease
Corneal abscess
Pigmentary keratitis
Immune mediated keratitis
Chronic superficial keratitis (pannus)
Lipid keratopathy
Corneal mineralization /calcification keratopathy
Corneal abscess
Uncommon
Intrastromal cellular accumulation
Infected vs sterile
Must vascularize to heal - medical vs surgical
Pigmentary keratitis
Not a specific disease - typically a result of underlying condition causing chronic irritation
Most common & severe in Brachycephalic dogs
Treat underlying conditions, topical cyclosporine or tacrolimus to clear pigment
