Corneal Ulcer in Shih Tzu — Management Guide

Practical, evidence-based guide to recognizing, diagnosing and managing corneal ulcers in Shih Tzus, including medical and surgical options and prevention.

Quick Overview

• What it is: A corneal ulcer is a loss of the corneal epithelium with or without deeper stromal involvement. Ulcers range from superficial erosions to deep, vision-threatening stromal ulcers and perforations.
• Who’s at risk: Brachycephalic breeds such as Shih Tzus are at increased risk because of prominent eyes, eyelid conformation (trichiasis/entropion), lagophthalmos (incomplete eyelid closure) and tear film abnormalities.
• Prognosis: Most superficial ulcers heal well with prompt treatment. Deep or infected ulcers, melting ulcers, or those that perforate carry a guarded to poor prognosis for the eye and vision if not treated quickly. Many ulcers resolve with medical therapy or minor surgery; complex repairs may be needed for deep ulcers.

Why Shih Tzus are prone to corneal ulcers

Shih Tzus are a brachycephalic (short‑muzzled) breed with large globes that sit prominently in the orbit. This conformation increases exposure of the cornea and makes the eye more likely to be scratched by hair, paws, or toys. Common contributing abnormalities include:

• Trichiasis (inward‑directed eyelashes) or distichiasis
• Medial canthal entropion or lateral entropion
• Lagophthalmos (incomplete eyelid closure) especially during sleep
• Tear film abnormalities and dry eye (keratoconjunctivitis sicca)

Pathophysiology (simple)

The cornea is a clear, layered structure. The epithelium (surface cells) forms the first barrier; beneath it is the stroma, a collagen-rich layer that provides most of the cornea’s thickness and strength.

• Superficial ulcer: loss of epithelium only. Usually painful but heals quickly.
• Stromal (deep) ulcer: loss extends into the stroma. Greater risk of infection, melting (enzymatic collagen breakdown) and perforation.
• Indolent (recurrent corneal erosion): the epithelium lifts off because of poor epithelial adhesion to the underlying basement membrane; the lesion may appear small but refuses to heal.

Symptoms and grading

Common signs in Shih Tzus:

• Squinting, excessive blinking (blepharospasm)
• Tearfulness or mucous/serous discharge
• Cloudy or white spot on the cornea
• Pawing at the eye or rubbing (use an Elizabethan collar to stop this)
• Redness of the conjunctiva
• Sometimes decreased vision if the ulcer is central

• Superficial ulcer: epithelium only (fluorescein positive, no stromal loss)
• Superficial stromal ulcer: <50% stromal depth involved
• Deep stromal ulcer: >50% stromal depth involved; may approach Descemet’s membrane
• Perforated: full‑thickness defect with aqueous leakage

Diagnostic approach

• Fluorescein stain: positive stain binds exposed stroma; essential first test.
• Schirmer tear test (STT): measure tear production; low STT (commonly <15 mm/min, <10 mm/min suspicious) predisposes to chronic problems.
• Neuro exam and intraocular pressure (tonometry) to rule out concurrent disease.
• Basic ophthalmic exam with magnification (ophthalmoscope/biomicroscope if available).

• Corneal cytology and culture: recommended for deep, malodorous, rapidly progressive, or failing ulcers to guide antibiotic therapy. Direct cytology (impression smear or scraping) can detect bacteria, fungi or neutrophils.
• Corneal thickness and depth assessment: slit lamp / biomicroscopy helps judge stromal involvement. B‑scan ultrasonography or referral imaging rarely needed unless the posterior segment is obscured.
• Immediate referral to a veterinary ophthalmologist when you see rapid progression, melting ulcers, hypopyon (pus in the anterior chamber), severe anterior uveitis, iris prolapse or globe perforation.

Overall principles: relieve pain, control infection, stop collagenase activity (melting), promote re‑epithelialization, and protect the cornea from further trauma.

Medical management (most superficial ulcers and some superficial stromal ulcers)

• Elizabethan collar: always until healed.
• Topical broad‑spectrum antibiotic drops: start immediately for traumatic ulcers. Choices include topical fluoroquinolones (ofloxacin 0.3%, ciprofloxacin 0.3%, moxifloxacin 0.5%) or aminoglycosides (tobramycin 0.3%) or chloramphenicol 0.5–1%. Typical dosing: q6–8h initially; severe cases q4h. For infected or deep ulcers, culture and sensitivity direct therapy.
• Topical atropine 1%: 1–2 times daily to effect for pain from ciliary spasm and to prevent synechiae; avoid in animals with glaucoma. Use cautiously in KCS because of reduced tear film.
• Systemic anti‑inflammatories/analgesia: NSAIDs (carprofen 2–4 mg/kg PO q12–24h) or opioids if severe pain (prescribed by your vet).
• Autologous serum or plasma: contains growth factors and anti‑collagenase activity. Often used at 20–50% concentration as eye drops q4–6h for indolent or melting ulcers. Prepare by your clinic or referral center; refrigerate and replace frequently.
• Topical anti‑collagenase agents: EDTA 0.05–0.1% drops and/or 1% serum; tetracyclines (doxycycline PO) have MMP‑inhibitory properties.
• Systemic antibiotics: indicated for deep stromal ulcers or risk of bacterial invasion. Doxycycline (5 mg/kg PO q12–24h) is useful for its anti‑collagenase effects in addition to antimicrobial activity. Amoxicillin‑clavulanate (12.5–20 mg/kg PO q12h) or other agents per culture results may be used.

Indolent ulcers and procedural debridement

Indolent ulcers usually require mechanical debridement of the nonadherent epithelium to allow healthy epithelial cells to migrate and reattach. Techniques include:

• Manual debridement with a sterile blade or spud under sedation/ topical anesthesia.
• Diamond burr debridement: a rotating burr gently roughens the basement membrane; many ophthalmologists prefer this over sharp debridement because of higher success and reduced re‑recurrence.
• Grid keratotomy: multiple superficial punctures in the cornea with a needle or blade to stimulate adherence. Historically effective, though not appropriate if the cornea is infected or the ulcer is deep. Contraindicated in young animals (risk of haze) and infected ulcers.

Surgical options for deep or complicated ulcers

• Conjunctival pedicle graft (or conjunctival flap): brings blood supply and mechanical support to a deep or melting ulcer; commonly used for deep stromal loss or when infection is severe.
• Superficial keratectomy: surgical removal of diseased stroma and epithelium; used with grafting as needed.
• Amniotic membrane or corneal grafts (including porcine or biosynthetic materials): used for tectonic support and to promote healing.
• Therapeutic corneal transplantation (grafting) for extensive loss or perforation: referral to a veterinary ophthalmology center.

Preventing recurrence — breed‑specific strategies

Because many contributing factors are anatomical in Shih Tzus, prevention often requires addressing the underlying problem:

• Eyelid and eyelash correction: removal of abnormal lashes (electrolysis or cryotherapy), medial canthoplasty to shorten the eyelid fissure and reduce exposure, or surgery for entropion.
• Treat dry eye (KCS) aggressively with topical cyclosporine 0.2–0.5% or tacrolimus and frequent lubrication. Maintaining a healthy tear film reduces risk of future ulcers.
• Routine grooming: keep facial hair trimmed away from the eyes; watch for corneal contact from hair and remove promptly.
• Protective measures: Elizabethan collar during high‑risk activities, avoid toys that may poke the eye.
• Regular ophthalmic checks: early detection of recurrent superficial defects or tear film problems.

• Recheck schedule: for uncomplicated superficial ulcers, recheck 24–48 hours after starting therapy, then every 3–5 days until healed. More frequent monitoring for deep or melting ulcers.
• Monitor for late complications: corneal scarring, pigmentation, vascularization (can affect vision), and chronic pain.
• If surgery was performed (e.g., conjunctival graft), follow up closely for graft viability, suture problems and signs of infection.

• Superficial ulcers: excellent prognosis with prompt care; usually heal fully with minimal scarring.
• Indolent ulcers: good prognosis after appropriate debridement; may recur if predisposing factors persist.
• Deep or infected ulcers: guarded to poor depending on depth, speed of progression, and whether the cornea perforates. With timely surgical intervention (grafts), many eyes can be saved, but some may lose vision or the globe.

• Keep face and periocular hair trimmed to avoid trichiasis.
• Use preservative‑free lubricating drops (e.g., carmellose 0.5% or hyaluronate) once to several times daily if tear film is marginal.
• Avoid smoky, dusty or chemically irritating environments.
• Maintain a first‑aid kit with an Elizabethan collar, ophthalmic lubricating gel, and contact information for your veterinarian and a local veterinary ophthalmologist.
• Be consistent with prescribed medications — missing doses delays healing.
• Observe daily for increased blinking, discharge, cloudiness, or pawing at the eye and seek prompt attention if signs arise.

Seek immediate veterinary care (same day) if your Shih Tzu shows any of the following:

• Sudden onset of severe squinting, eye pain, or continuous pawing at the eye
• A rapidly changing cloudy/white corneal lesion
• A dark brown or pus‑colored ocular discharge
• Sudden blindness or dilated pupil with corneal changes
• Any sign of tissue prolapse (pink tissue in the cornea) or suspected perforation

• American College of Veterinary Ophthalmologists (ACVO) client information and guidelines on corneal ulcers and appropriate referral. https://www.acvo.org/animal-owners/conditions/corneal-ulcer/
• Gelatt KN. Veterinary Ophthalmology (standard textbook). Comprehensive chapters on corneal disease, indolent ulcers, and surgical management.
• Veterinary Ophthalmology journal — multiple studies on debridement, diamond burr success and outcomes for indolent and melting ulcers.

This guide is for educational purposes. Always consult your veterinarian for diagnosis and treatment.

Frequently Asked Questions