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Corneal Ulcers with Endothelial Dysfunction – Gundersen Flap, Corneal Cross-Linking, Thermokeratoplasty

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Corneal Ulcers with Endothelial Dysfunction – Gundersen Flap, Corneal Cross-Linking, Thermokeratoplasty Louise O’Leary, ISU Canine Ulcerative Ophthalmology Resident 2019 Keratitis – The Good, the Bad and the Ugly • Corneal Anatomy • Definitions Areas • Causes Covered • 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 Complicated Simple ulcer: ulcer: heals in < 7 involves days without stroma and/ stromal or persists involvement longer than 7 days Causes Inadequate corneal Excessive epithelial loss protection • Trauma* • KCS* • Foreign body • Macropalpebral fissure • Primary pathogen – herpesvirus* • Lagophthalmos • Distichiasis, ectopic cilia, • Qualitative tear deficiencies trichiasis* • Facial nerve dysfunction • Entropion • Trigeminal nerve dysfunction • Lid tumours • Ectropion • 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 https://veteriankey.com/ cornea/ http://www.theveterinaryexpert.com/ Vettimes.co.uk eyes/corneal-ulcers-in-dogs-and-cats/ Dendritic Vin.com Stromal Descemetocoele Indolent Diagnosis – Staining Patterns 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 Nevile et al 2015 Vet Ophtho medications, +-/ systemic antibiotics 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 https://www.cliniciansbrief.com/article/ corneal-conjunctival-cytology culture – culture margin • Reapply topical anaesthetic for cytology • Cytology – cytobrush, kimura spatula, back of scalpel blade Thehorse.com Corneal Cytology Evaluation • Examine for presence of microorganisms – Eclinpath.com Nevile et al 2015 Vet Ophtho rods/cocci, fungal hyphae • Examine for presence of inflammatory cells Eclinpath.com Management – Corneal Rupture Vettimes.co.uk • 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 Merckveterinarymanual.com • +/- Sedatives Seidel Test • Assess for leakage of aqueous https://webeye.ophth.uiowa.edu/eyeforum/atlas/pages/corneal- humour perforation-seidel-posative-.html Management - Keratomalacia Vettimes.co.uk • Aggressive, frequent medical therapy q30mins -1 hr • Anti-proteases - Serum/plasma https:// - Systemic doxycycline 10mg/kg PO SID www.medvetforpets.com/ new-treatment-corneal- ulcers/ - EDTA, n-acetylcysteine • Atropine, e-collar, anti-inflammatories etc • Surgery http:// • Cross-linking ophtalmoveterinaire.com/en/ 2016/02/03/ulcere-corneen- infecte/ 1. Instigating factor still present: e.g. distichia, ectopic cilia, entropion 3 Reasons Ulcers Fail to 2. Infection is present Heal 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 https://pdfs.semanticscholar.org/ • Contraindicated in 6634/0a4dcc8538f9da1b82fa8b016f701efdec5c.pd cats! f When to Refer Routine 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??.
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