Canine Ulcerative Keratitis – The Good, the Bad and the Ugly

Louise O’Leary, ISU Ophthalmology Resident 2019

Areas Covered

• Corneal Anatomy • Definitions • Causes • Diagnosis • Management •When to refer?

Corneal Anatomy

4 layers • Epithelium • Stroma • Descemet’s

membrane • Endothelium

https://www2.vetmed.ucdavis.edu/courses/vet_eyes/eye_path/epath_overview_index.html

Definitions

• Abrasion/erosion: partial thickness epithelial loss • Ulcer: full thickness corneal epithelial loss • SCCEDS/Indolent ulcer: refractory superficial corneal ulcer w/non-adherent epithelial margins • Descemetocoele: extends to Descemet’s membrane

Classification

Simple ulcer: heals in < 7

days without stromal

involvement

Complicated ulcer:

involves stroma and/or persists

longer than 7 days

CausesInadequate corneal protection • KCS* • Macropalpebral fissure • Lagophthalmos • Qualitative tear deficiencies • Facial nerve dysfunction • Trigeminal nerve dysfunction • Ectropion

Excessive epithelial loss • Trauma* • Foreign body • Primary pathogen –

herpesvirus* • Distichiasis, ectopic cilia,

trichiasis* • Entropion • Lid tumours • Blepharitis

Clinical Signs

• Blepharospasm • Pawing/Rubbing • Epiphora • Conjunctival hyperemia • Corneal opacity • +/- Visible corneal lesion/defect •Miosis

Diagnosis – Corneal Stains

• ** Obtain STT first ** • Fluorescein – true ulcers • Rose Bengal/Lissamine Green – abrasion/erosion, qualitative tear deficiency

Diagnosis – Staining Patterns

DendriticIndolent

Stromal Descemetocoele

https://veteriankey.com/cornea/

Vin.com

http://www.theveterinaryexpert.com/eyes/corneal-ulcers-in-dogs-and-cats/

Vettimes.co.uk

Evaluation of Ulcer

• Assess depth: slit beam direct ophthalmoscope

• Assess for infection: - white/yellow infiltrate

- stromal loss - degree of uveitis

Determining Cause

Thorough ophthalmic examination with magnification: • Assess tear film health: STT (+/- Rose Bengal, +/- TFBUT) • Assess for trichiasis • Assess lid closure: palpebral reflex, +/- corneal reflex • Assess palpebrae: ectopic cilia, distichiasis, lid tumours, conformation • +/- Check behind 3rd eyelid

Management – Simple Ulcer• Prophylactic broad spectrum

topical antibiotic – neopolybac, neopolygram, terramycin, etc – QID • Atropine

• Systemic anti-inflammatories/pain meds (nsaids, steroids) • **HARD PLASTIC E-COLLAR** at all

times RECHECK - within 3-5 days

Management - Stromal/Infected Ulcer• ** Cytology and Culture** • Broad-spectrum ab coverage: 2 different abs empirically • Serum/Plasma •Min 6-8x day, up to q1-2 hours depending on severity • Atropine • E-collar • Systemic anti-inflammatories/pain medications, +-/ systemic antibioticsNevile et al 2015 Vet Ophtho

Broad Spectrum Antibiotic Choice

• Gram positive: chloramphenicol, cefazolin, neopolybac, neopolygram, ofloxacin, ciprofloxacin, terramycin,

• Gram negative: tobramycin, gentamicin, ofloxacin, ciprofloxacin, neopolybac, neopolygram, terramycin

Sampling – Culture and Cytology

• 1 drop proparacaine prior to culture – culture margin • Reapply topical anaesthetic for cytology • Cytology – cytobrush, kimura spatula, back of scalpel blade

https://www.cliniciansbrief.com/article/corneal-conjunctival-cytology

Thehorse.com

Corneal Cytology Evaluation• Examine for presence of microorganisms – rods/cocci, fungal hyphae • Examine for presence of inflammatory cells

Eclinpath.com Nevile et al 2015 Vet Ophtho

Eclinpath.com

Management – Corneal Rupture• Considerations: Seidel test, dazzle/

consensual, finance, owner goals • **Culture and Cytology** • Aggressive medical therapy • Systemic antibiosis • Atropine, anti-inflammatory, e-collar

etc • Fragile eye care • +/- Sedatives

Vettimes.co.uk

Merckveterinarymanual.com

Seidel Test• Assess for leakage of aqueous humourhttps://webeye.ophth.uiowa.edu/eyeforum/atlas/pages/corneal-

perforation-seidel-posative-.html

Management - Keratomalacia• Aggressive, frequent medical therapy

q30mins -1 hr • Anti-proteases

- Serum/plasma - Systemic doxycycline 10mg/kg PO SID - EDTA, n-acetylcysteine

• Atropine, e-collar, anti-inflammatories etc • Surgery

• Cross-linking

Vettimes.co.uk

https://www.medvetforpets.com/new-treatment-corneal-ulcers/

http://ophtalmoveterinaire.com/en/2016/02/03/ulcere-corneen-infecte/

3 Reasons Ulcers Fail to Heal

1. Instigating factor still present: e.g. distichia, ectopic cilia,

entropion

2. Infection is present

3. Indolent ulcer

Indolent Ulcers/SCCEDS• Chronic ulcers with

loose edges • > Middle aged • Boxers, any breed • Characteristic staining • Appearance: +/-

neovascularization, corneal oedema, superficial, raised/folded edges, +/- uveitis, +/- pain

Histopathology – Indolent Ulcer

https://vetcares.com/scced/

Management – Indolent Ulcer Pt.1• **E-COLLAR** • Topical abs QID • Systemic pain medications • +/- Contact lens* • +/- Atropine • +/- Serum RECHECK: 10-14 days

Management - Indolent Ulcer Pt. II• Cotton-tipped

applicator debridement • Diamond burr • Grid keratotomy/

anterior stromal puncture • Corneal glue • Thermokeratoplasty • Superficial

keratectomy

Cotton-Tipped Applicator Debridement

• Success rate – approx. 30-50% • Removes loose epithelium • Easy • Low risk • Repeatable • Be aggressive!

https://www.ndsr.co.uk/en-GB/specialist-referral-service/pet-health-information/ophthalmology/recurrent-corneal-erosions

Diamond Burr Debridement • Prep well – sterile surface • Remove lose edges w/CTA

first • Gentle pressure over ulcer

bed approx. 60-90 seconds • Easy, repeatable, minimal

scarring • Risk of seating infection

deeper https://www.alloymedical.com/algerbrush-ii-diamond-instrument-for-smoothing-corneal-scleral-edges-brpt-rm-medium-round-unit-with-35mm-pterygium-diamond-burr-chi-678

Grid Keratotomy/Anterior Stromal Puncture•Local +/- sedation, +/- GA

•Prep well – sterile surface

•25 g needle •100-150 lines extending 1-2mm past periphery

•Greater risk

•Contraindicated in cats!

https://pdfs.semanticscholar.org/6634/0a4dcc8538f9da1b82fa8b016f701efdec5c.pdf

When to ReferRoutine appt: •Non-healing indolent ulcers – DBD, grid, superficial keratectomy • Recurrent corneal ulcers with endothelial dysfunction – Gundersen flap, corneal cross-linking, thermokeratoplasty

EMERGENT REFERRALS: • Deep corneal ulcers - > 50% corneal thickness lost – surgery recommended • Keratomalacia- surgery, corneal cross-linking

References• Ledbetter EC, Gilger BC. Diseases and surgery of the canine cornea and sclera. In: Gelatt KN, Gilger BC, Kern TJ, editors. Veterinary

Ophthalmology. Ames, IA: Wiley-Blackwell; 2013. pp. 976–1049.

• Ellison Bentley , DVM, DACVO Christopher J. Murphy , DVM, PhD, DACVO. (2004) Thermal cautery of the cornea for treatment of spontaneous chronic corneal epithelial defects in dogs and horses. Journal of the American Veterinary Medical Association 224:2, 250-253. 

• Miller T, Gilger B, Maggio F, Davidson M. Use of thermokeratoplasty for treatment of ulcerative keratitis and bullous keratopathy secondary to corneal endothelial disease in dogs: 13 cases (1994–2001). Journal of the American Veterinary Medical Association. March 1, 2003, Vol. 222, No. 5, Pages 607-612

• Chandler H, Metzler A, Bras D et al. In vivo effects of adjunctive tetracycline treatment on refractory corneal ulcers in dogs. Journal of the American Veterinary Medical Association. August 15, 2010, Vol. 237, No. 4, Pages 378-386

• Dees, D. D., Fritz, K. J., Wagner, L. , Paglia, D. , Knollinger, A. M. and Madsen, R. (2017), Effect of bandage contact lens wear and postoperative medical therapies on corneal healing rate after diamond burr debridement in dogs. Vet Ophthalmol, 20: 382-389.

• Spiess, BM, Pot, SA, Florin, M et al. Corneal collagen cross-linking (CXL) for the treatment of melting keratitis in cats and dogs: a pilot study. Veterinary Ophthalmology 2013.

• 16 Pot, SA, Gallhofer, NS, Matheis, FL et al. Corneal collagen cross-linking as treatment for infectious and noninfectious corneal melting in cats and dogs: results of a prospective, nonrandomized, controlled trial. Veterinary Ophthalmology 2013

• Pot, S. A., Gallhöfer, N. S., Walser-Reinhardt, L. , Hafezi, F. and Spiess, B. M. (2015), Treatment of bullous keratopathy with corneal collagen cross-linking in two dogs. Vet Ophthalmol, 18: 168-173. 

• Horikawa T, Thomasy SM, Stanley AA, et al. Superficial Keratectomy and Conjunctival Advancement Hood Flap (SKCAHF) for the Management of Bullous Keratopathy: Validation in Dogs With Spontaneous Disease. Cornea. 2016;35(10):1295-304.

QUESTIONS??