Sclera, Conjunctiva, Cornea Flashcards
Sclearitis
Usually immune mediate and in conjunction with uveitis. Can be treated with corticosteroids (topical idea, systemic), azathioprine (more powerful. You are aiming for control not cure.
Conjunctivitis
Very fine branching, usually doesn’t bulge out unless there is infection (edema = chemosis). With disruption you will usually have increased ocular discharge, starting to be serous with excess tear production and then if there is a secondary bacterial infection then muco-purulent.
Etiologies for conjunctivitis
KCS (major cause)
Corneal ulceration/abrasion
Intraocular disease
Bacterial/Viral/Allergy
Diagnosis & therapy for conjun
Cutlrure , biopsy, cytology
Therapy: broad spectrum antibiotics/with possible steroids
Follicular conjunctivitis
Usually for young dogs. Lymphoid hyperplasia/conjunctival hyperaemia
Debride follicles with cotton swab
Antiobiotic steroid therapy (Topical TID)
Conjunctival haemorrhage
- Haemorrhage located between conjunctiva and sclera
- Trauma, coagulopathy, systemic hypertension
- Treat underlying problem – Time is on your side!
Conjunctival neoplasia
Can be benign or malignant
Hemangiomas & hemangiosarcomas
What is the function of the cornea
- Light refraction (corneal curvature bends light rays as they enter; major refractive surface of the eye)
- Light transmission (Transparency: dehydrated layer, parallel arrangement of collagen, lack of cells/blood vessels/pigments)
What is the nutrition for the tear film/aqueous
Tear film: oxygen, glucose
Aqueous fluid: Oxygen, glucose, protein, lipids, enzymes, electrolytes
White in the cornea - causes
White = probably lipid (genetic, too much in the diet) or calcium
Grey cornea
Grey = more of a scar.
Black cornea
Sometimes pigmentations can be a black scab on the cornea (sequestrum)
Brown in the middle = iris poking through. Will come up to plug the dam
Corneal Healing/Stroma
• Keratocytes proliferate, become fibroblasts
– 24 hours
• Collagen fibers form into bundles
• Scar: if collagen bundles disorganized
Corneal Healing: Endothelium
- Spreading and enlargement of cells
* Replacement of basement membrane • Corneal edema if defect too large
Ulcerative Keratitis
Means corneal ulcerations. There is no epithelium, possibly some stromal loss (variable)
Most are due to trauma with secondary bacterial infection, very few bacteria can cause it on their own. KCS can set it off on its own.
Ulcerative Keratitis - diagnosis
• Ocular exam: Identify mechanical causes
• STT: >15 mm/min
• Fluorescein stain:
– Positive: stromal
– Negative: Descemetocele
• Cytology: bacteria, fungal, inclusion bodies • Culture: bacterial and fungal sensitivity
Types of corneal ulcers
Simple - superficial non-infected
Complex/Deep Ulcer - could go to deceme’s membrane, could rupture
Refractory ulcer- superficial/non-infected but doesn’t want to eal.
Simple corneal ulcers
• Acute superficial ulcer • No: – Infiltrate – Vascularization – Pigmentation • Painful – Miotic pupil
Complicated corneal ulcers
- Acute or chronic
- Varies in depth – Descemetocele
- Corneal infiltrate
- Edema
- Vascularization – If chronic
- +/- Melting
Refractory Ulcers
• Chronic ulcer – Not responding to therapy • Loose epithelial edge • No infiltrate • Diffuse staining – Halo 
Treatment for corneal ulcers
• General considerations:
– Identify type of ulcer
– Frequency of medication: better too often
– Drops versus ointment
– If no positive response in 24-48hrs
• Re-evaluate therapeutic protocol
– Topical Steroids and NSAIDs: contraindicated! (Unless there is something more vision threatening)

Treatment for simple corneal ulcers
• Correct mechanical causes
• Broad-spectrum antibiotics QID
• +/- Atropine
– Verify STT: lubricate if necessary
• Elizabethan collar • Recheck: 3-5 daysTreatment for complicated corneal ulcers
• Debride / flush
– Dilute iodine to disinfect
• Topical bactericidal antibiotics q1-2 hours • Serum: melting
• Atropine: BID then to effect
• Systemic NSAIDs
• Recheck: within 24 hours if severe
• Surgery: keratectomy, conjunctival graft
Treatment for refractory corneal ulcers
Grid keratotomy
– Topical anesthetic, sedation, GA
• Prophylactic bacteriostatic antibiotic QID
• Atropine: BID 3 days
• Contact lens - remove within 3 days – Alternative: third eyelid flap
• Recheck: 7 days
• May take up to 30-40 days to heal
Pigmentary Keratitis
Often in a pug, pigment on the corneal (Melanocyte in epithelium), will start on the medial canthus due to chronic irritation, KCS • STT, Fluorescein stain • Remove irritation • Lubrification • Steroids, cyclosporine
Chronic Superficial Keratitis
- Neovascularization and pigment • Immune-mediated
- German Shepherd, greyhounds
- Cytology: plasma cell
- Steroid, cyclosporine • No cure
Dystrophy vs. Degeneration in cornea
Corneal dystrophy • Inherited • Bilateral / symmetrical • Primary disorder • Central cornea • No vascularization • No blindness
Corneal degeneration • Acquired • Unilateral/asymmetric • Underlying disease • Anywhere • Vascularization • May lead to ulcer
Endothelial inflammation
• Secondary to uveitis – Vaccine reaction • Fluorescein negative • Steroids: – Topical and systemic
Endothelial Dystrophy
• Abnormal endothelial cells – Leading to corneal edema • Epithelial bullae formation – Results in chronic ulcers • Penetrating keratoplasty • Thermokeratoplasty 
Corneal Masses
• Nodular granulomatous episcleritis (NGE)
– Raised mass
– Diagnosis: biopsy
– Steroids, tetracycline/niacinamide/azathioprine
Dermoid
Hairy eyeballs
If taken off properly they shouldn’t grow back. Skin cells have lost heir way & implanted themselves. Operating microscope & delicate scapel blade to cut them out and leave the corneal to heal by second intention (ulcer)
Corneal neoplasia etc.
• Hemangioma/sarcoma
– Vascular lesion onto cornea from limbus • Keratectomy
– Followed by cryotherapy or radiation
