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Complicated corneal ulcer: Avoiding disasters (Proceedings)
The primary goal in treating a corneal ulcer is to identify its cause or identify factors that may prevent it from healing well.
1. Corneal erosion: Superficial: Epithelium
2. Corneal ulcer: Middle: Stroma
3. Descemetocoele: Deep: Endothelium and Descemet's membrane
Most Corneal Ulcers Occur for a Reason
1. Abnormal tear film
2. Abnormal blink motion
3. Decreased corneal sensation
4. Abnormal hairs
The primary goal in treating a corneal ulcer is to identify its cause or identify factors that may prevent it from healing well. Therefore a thorough ocular examination should be performed on any patient with an ulcer.
a. Distichia- breed predisposition
b. Ectopic cilia- young dogs, very painful, dorsal erosion
c. Trichiasis- entropion
a. ulcer depth
b. ulcer character (malacic, infected, indolent)
4. Anterior chamber
a. uveitis (primary or reflex?)
7. Posterior segment
1. Schirmer Tear Test
a. Normal 15-25, but brachycephalic?
2. fluorescien stain
a. Stains stroma only, will delineate ulcer size
b. TFBUT >20 seconds
c. Undermining epithelial lip?
a. Ulcers can commonly occur secondary to rubbing from glaucoma discomfort.
1. Treat the underlying cause.
- Surgery for hair removal
- Tear stimulant therapy
- Glaucoma therapy
2. Manage concurrent problems.
- Systemic antibiotics
- Systemic anti-inflammatories
3. Choose antibiotic therapy based on severity of ulcer and predisposition to get worse.
- Triple antibiotic or Gentocin good first line defense
- Tobramycin for pseudomonas infections
- Tobramycin AND Ofloxacin for complicated ulcers
- Plasma for malacic ulcers
4. Consider supportive care.
- Tear replacement therapy
5. Determine if depth warrants surgical correction. (>50% consider)
- Conjunctival pedicle graft
- Cornealconjunctival transposition
- Island graft
- Artificial membrane tissue graft
1. If an ulcer is not healing- simply changing antibiotics is not the best approach!
2. Remember atropine will decrease tear production- only use if needed.
Various Complicated Ulcers
- Age related, usually no breed predisposition
- mineral accumulation resulting in corneal tissue sloughing
- Difficult to heal with medication
- Trichlorocetic acid debridement or CPG
- Age related, breed predisposed (dalmation, dachshund, boston terrier)
- Loss of endothelial cells resulting in accumulation of edema in cornea
- Results in mild to moderate loss of vision
- Can cause corneal bullae and subsequent ulcers and erosions.
- Sodium chloride ointment can slow progress of disease
- Erosions and recurrent bullae treated with laser keratoplasty
Multiple superficial punctuate keratitis
- Breed related (usually Shetland Sheepdog)
- Immune-mediated disease with mulitfocal erosions
- Immunosuppressive therapy required, often for life
Herpes corneal erosions
- Feline chronic issues, epithelial in nature
- Client education is a large treatment!
- Topical antivirals may be necessary
- Preventative therapy includes Genteal gel and L-Lysine
- Diagnostic undermining of erosion edges, do not need recurrence
- Q-tip debridement, linear grid keratotomy, multiple punctuate
- keratotomy, superficial keratectomy
Corneal foreign bodies
- Typically removal out the entrance wound
- Beware of possible AC penetration, be prepared for corneal wound surgery
- Very close examination to determine if ANY lens involvement—may need phacoemulsification