Corneal Ulcers Andrew Enders, DVM Resident, Ophthalmology
Normal Corneal Anatomy Four layers Epithelium Stroma Descemet s membrane Endothelium Total thickness Canine 500-650 um Feline 500-700 um http://www.vetmed.ucdavis.edu/courses/vet_eyes/eye_path/ epath_overview_index.html Organized lamellae span the diameter and are separated by less than the distance of a wavelength of light Avascular, highly innervated, clear refractive surface
Causes of Corneal Ulcers Trauma Adnexal disease Tear film deficiency Exposure Examples include: Cat scratch Foreign bodies (organic and inorganic) Self induced?? Chemical burns (shampoo) Entropion Ectropion Ectopic cilia Distichia Quantitative KCS Qualitative KCS Facial paralysis Neurotrophic keratitis Lagophthalmos
Corneal Ulcer Diagnostics Search for underlying cause Schirmer tear test ALWAYS! Fluorescein stain Corneal culture Specific Indications Corneal cytology
Fluorescein stain Hydrophillic Stroma picks up stain Full strip vs. diluted Rinse! Rinse! Rinse! When to stain? Don t get foiled by facets!
Corneal culture and cytology Culture Prior to the administration of any topical medications Aerobic always with sensitivity +/- anaerobic +/- fungal Cytology Spatula Scalpel blade Cytobrush Cotton tip Impression cytology May help you save the eye before microbiology tells you what to do Positive cytology and negative culture common
Descriptions of Corneal Ulcers Depth Superficial ulcers Anterior stromal Mid-stromal Deep stromal Descemetocele Corneal perforation Taller than the cornea?? Time and Complexity Acute Any depth Chronic Truly only superficial Simple Complicated Any depth Infection Coexisting disease (KCS) Keratomalacia
Keratomalacia
Normal corneal healing Reepithelialization Migration Mitosis Epithelialization begins in as little as 24 hours after injury. Under normal circumstances, corneal ulcers generally heal within 7-10 days. Often much quicker! Secondary collagen formation occurs weeks to months later. Or may not occur Nagata et al. JBP485 promotes corneal epithelial wound healing. Scientific Reports. 2015
Descriptions give you expectations Acute superficial ulcer Heal Mid-stromal ulcer Deep stromal ulcer Chronic superficial ulcer Descemetocele Corneal perforation
Expectations Medical or Surgical? Medical Disease Acute superficial ulcer Mid-stromal ulcer Chronic superficial ulcer Deep stromal ulcer Descemetocoele Corneal perforation Surgical Disease
Assess the patient for risk factors Is tear production normal? Can and does the animal blink normally? Brachycephalic breed/conformational exophthalmos? Adnexal abnormalities? Does ulcer appear infected/malacic?
Brachy rule breakers
Goals of Therapy Prevent self trauma HARD E-Collar Prevent/control infection Topical antimicrobials Prevent/control collagenolysis Topical and systemic anti-collagenases Increase patient comfort Topical atropine, systemic NSAIDs Promote healing Topical autogenous serum
Prevent self trauma Google images
Topical Antimicrobials Topical broad spectrum antibiotics or as directed by culture and sensitivity Empiric choice dictated by characteristic of ulcer Frequency dictated by severity of ulcer Systemic antibiotics have little to no application in managing corneal ulcers
Antimicrobial Therapy Superficial ulcers Goal of therapy = prophylaxis Options: NeoPolyBac PolyBac (cats) NeoPolyGram Gentamicin Tobramycin Terramycin Erythromycin Ofloxacin Ciprofloxacin Ulcers with depth Goal of therapy = treat known or suspected infection Combination therapies Ciprofloxacin Gatifloxacin Moxifloxacin Cefazolin Chloramphenicol Dictated by cytology and culture
Topical Antimicrobial Resistance is a growing problem!
Topical Antimicrobial Resistance is a growing problem!
Systemic Antimicrobials No use in treating corneal ulcers Without a vascular supply that has infiltrated the ulcer bed (i.e. conjunctival pedicle flap) systemic antibiotics do not reach the target area.
Anti-Proteolytics Agents Topical autogenous serum May also speed corneal epithelial growth Topical N-acetylcysteine 2-10% solution Topical EDTA 2-10% solution Tetracyclines Systemic doxycycline, minocycline What about topical tetracyclines?
Pain management Topical atropine Provides cycloplegia (ciliary body relaxation) Systemic NSAIDs Control pain and intraocular inflammation System Opioids, Neuropathic modulators
NSAIDs and ulcers Use topicals with caution.
Topical opioids and ulcers
Corneal Repair Gels Marketed as Corneal Repair Gel drops to promote corneal healing by supporting the natural healing processes of superficial corneal ulcers. It can be beneficial or desired for treatment of superficial corneal ulcers. Active ingredients 0.2% HA or 0.75% modified cross linked HA. *Not to be used as a sole therapy for superficial corneal ulcers; does not contain an antibiotic. So what s the science?
Nasty Ulcers
Deep Stromal Ulcers/Melting Ulcers Diagnostics are essential! Investigate underlying factors Culture and sensitivity Corneal Cytology
Deep Stromal Ulcers/Melting Ulcers Treatment E collar Topical antibiotics Broad spectrum Directed by cytology, culture, and sensitivity Should likely have a fluoroquinolone on board Frequency q 1-4 hours Solutions over ointments Protease inhibitors Systemic doxycycline, minocycline Topical autologous serum q 1-4 hours Topical EDTA Pain control Topical atropine as needed to dilate pupil (remember to check STT) Oral NSAID +/- opioid or other Follow up Hospitalize or recheck in 24 hours
When to refer? Ulcers greater than 50% depth may require surgical stabilization Worth putting the bug in the owners ear Deep ulceration/descemetoceles should be referred Descemetoceles will NOT heal medically Progression or failure to stabilize within 24-48 hours Diminished discharge Increased comfort Epithelial ingrowth
What NOT to do DO NOT DEBRIDE TO STIMULATE HEALING. It is always inappropriate to debride any ulcer with depth. Third eyelid flap If protection is necessary, partial tarsorrhaphy is a better option Start with a conservative treatment approach, planning to get more aggressive if necessary Initiate treatment and recheck several days later Especially in brachycephalic animals
The Never Ending Ulcer
Non-Healing Ulcers Indolent Ulcer is a misnomer Synonyms: Boxer ulcer, refractory ulcer, recurrent erosion, chronic ulcers, indolent ulcers SCCED Spontaneous Chronic Corneal Epithelial Defect The name explains the disease No underlying cause, non-healing, SUPERFICIAL corneal ulcer Most common in middle-aged dogs Corgis and Dalmatians
Non-Healing Ulcers Indolent Ulcer Unresolved source of corneal abrasion Distichia Ectopic cilia Entropion Foreign body KCS All SCCEDs are indolent ulcers Not all indolent ulcers are SCCEDs Exposure keratitis Neurotrophic keratitis Corneal infection SCCED
Not SCCED!
Not SCCED!
Not SCCED!
Not SCCED!
Characteristics of SCCED Chronic superficial ulcer Epithelial lip with fluorescein halo Variable pain and vascularization May change in size or dance around the cornea VERY rarely become infected
Pathogenesis of SCCED Not well understood Similar to non healing ulcers is other species Hyalinized anterior stromal acellular zone prevents epithelial adhesions Addressing this maladhesion is the goal of therapy.
SCCED Treatment Debridement is required to heal Surgical procedures Cotton tip debridement (30-50%) Grid or punctate keratotomy (80-90%) Diamond burr keratotomy (90%) Superficial keratectomy (100%) As with all corneal ulcers, topical antibiotics are applied until healed Solutions vs ointments E collar +/-Bandage contact lens Debridement with adjunctive therapy (30-80%) Topical EGF, GAGs, apoprotinin, substance P, PRP, chondroitin sulfate, oral and topical tetracyclines, insulin-like GF-1, HA, aminocaproic acid, thermal cautery Corneal cyanoacrylate tissue adhesives glue (100%)
Epithelial debridement (CTA) 30-50% chance of healing Can usually perform with topical anesthesia alone Tips: change the CTA often, debride vigorously, ulcer should be significantly larger, prepare owners for failure
Anterior Stromal Puncture Techniques Grid keratotomy, Punctate keratotomy, Burr Keratotomy Penetration of the zone of anterior hyalinized stroma THIS IS THE ONLY TYPE OF CORNEAL ULCER WHERE THIS SHOULD BE PERFORMED!!! Must perform a CTA first to outline the margins of the ulcer to debride 25 gauge needle with bent tip Lightly scratch the ulcer bed and extend into normal tissue ~2 mm i.e begin and end in normal epithelium Scratches ~1 mm apart
Algerbrush II Burr
Postoperative Keratotomy Management Treatment E collar Topical antibiotic TID until healed Oral NSAID 85-90% healed within 10-14 days +/- bandage contact lens Recheck Recheck once weekly for Fluorescein stain If not healed in 2 weeks Treatment should be repeated
Common Mistakes in Managing SCCED Repeatedly switching antibiotics due to healing failure These are not infected Inadequate debridement Be aggressive! Debridement alone Doesn t work in most cases Debridement during course of healing Wait at least 2-3 weeks before repeating may require up to 6 weeks for complete development of epithelial adhesion complexes
Bandage Contact Lens and SCCED
Bandage Contact Lens and SCCED
Serum and SCCED
Questions??