A clinical guide to canine corneal ulcers. Learn to stage simple vs. melting ulcers and descemetoceles, use fluorescein stain logic, perform indolent ulcer procedures, and monitor safety.

A dog that presents with a squinting, red, and watery eye is one of the most common acute ophthalmic visits in small-animal primary care. While many owners assume their dog simply has conjunctivitis or got something dirty in their eye, the clinical reality is often a corneal ulcer—a loss of the outer epithelial layer of the clear window of the eye.

For a veterinary team, diagnosing a corneal ulcer is straightforward, but managing it requires careful staging and strict compliance. For a dog owner, navigating an eye injury is highly stressful: the eye is a delicate, pain-sensitive organ, and a superficial scratch can rapidly escalate into a sight-threatening emergency.

Understanding the depth of the ulcer, the diagnostic logic of the fluorescein stain test, the clinical necessity of ciliary-spasm pain relief, and why self-trauma prevention (the Elizabethan collar, or "cone") is non-negotiable is critical to preserving a dog's vision.

Fast Answer: Triage and Treatment Summary

A corneal ulcer is a scratch, scrape, or erosion on the clear surface of the eye. It is diagnosed using a fluorescein stain test, where an orange-yellow dye is applied to the eye; if the protective outer cell layer (the epithelium) is missing, the dye adheres to the underlying stromal tissue and glows bright green under a cobalt blue light.

Most corneal ulcers are simple, superficial wounds that heal within 5 to 7 days using a standard protocol: prophylactic topical antibiotic drops, atropine drops to relieve painful muscle spasms inside the eye, and an Elizabethan collar (cone) worn 24/7.

However, corneal ulcers can be highly unstable. If bacteria colonize the wound, they can release enzymes that digest the cornea, leading to a "melting" ulcer. If the erosion reaches the deepest layer, it forms a descemetocele—a bubble-like structure that represents the final thin barrier before the eye ruptures.

A corneal ulcer is an after-hours emergency if you observe:

A sudden worsening of pain (increased squinting, pawing at the eye, or vocalizing).
Dense, yellow-green, or purulent discharge pooling in the eye.
A blue, cloudy, or intensely red appearance across the entire eyeball.
A visible dent, crater, or "bubble" on the surface of the cornea.
The dog has had direct trauma to the eye (such as a cat scratch, which introduces high-risk bacterial pathogens deep into the stroma).

Never discontinue prescribed eye drops or remove the cone until a veterinarian has performed a repeat fluorescein stain test and confirmed that the epithelium has fully closed.

What is a Corneal Ulcer, and How Does the Fluorescein Stain Work?

To understand how a corneal ulcer behaves, it is necessary to examine the anatomical structure of the canine cornea. The cornea is a highly specialized, transparent tissue composed of five distinct layers in dogs (and cats), though three are of primary clinical focus:

The Epithelium: This is the outermost layer, consisting of several strata of non-keratinized squamous epithelial cells. It serves as a physical barrier against pathogens, debris, and tear fluid. The epithelium is constantly shedding and regenerating, and it is highly resistant to fluid absorption.
The Stroma: Comprising approximately 90% of the corneal thickness, the stroma consists of highly organized, parallel collagen fibrils suspended in a ground substance of glycosaminoglycans. This precise arrangement is what makes the cornea transparent. Unlike the epithelium, the stroma is hydrophilic—it eagerly absorbs water.
Descemet's Membrane: This is a thin, elastic, acellular basement membrane secreted by the underlying endothelium. It is hydrophobic and represents the final structural barrier of the cornea.
The Endothelium: A single layer of hexagonal cells lining the inner surface of the cornea. These cells act as active metabolic pumps, constantly pumping fluid out of the stroma and back into the anterior chamber of the eye to keep the stroma dehydrated and clear. If the endothelium fails or is damaged, the stroma swells with fluid, turning the eye blue and cloudy.

A corneal ulcer occurs when there is a disruption or loss of the epithelial layer, exposing the underlying stroma.

The Mechanics of the Fluorescein Stain

Fluorescein is a water-soluble, hydrophilic dye that fluoresces bright green under blue or ultraviolet light. Because the intact corneal epithelium is hydrophobic and rich in lipids, fluorescein cannot adhere to it; the dye simply washes away with the tear film.

However, when the epithelium is damaged or missing, the hydrophilic stroma is exposed. The fluorescein dye binds rapidly to the exposed stromal collagen fibers. When the eye is flushed with sterile saline to rinse away excess dye, the area of epithelial loss retains the stain, highlighting the exact boundaries, shape, and depth of the ulcer.

Intact Cornea:
[ Tear Film ] -> washes away fluorescein
=================================== (Epithelium - Hydrophobic)
||||||||||||||||||||||||||||||||||| (Stroma - Hydrophilic)
----------------------------------- (Descemet's Membrane)

Ulcerated Cornea:
      [ Fluorescein Dyes Exposed Stroma Green ]
      \________   ________/
===============   ================= (Epithelium Lost)
|||||||||||||||   ||||||||||||||||| (Stroma Exposed & Stained Green)
----------------------------------- (Descemet's Membrane)

In a clinical workup, the veterinarian will gently apply a fluorescein-impregnated paper strip moistened with sterile saline to the conjunctiva, allow the dog to blink to distribute the dye, and then flush the eye thoroughly. They will then inspect the eye in a darkened room using a transilluminator equipped with a cobalt blue filter.

If the green stain is retained, the test is positive, confirming a corneal ulcer. This test is crucial for differentiating a surface scratch from other causes of a red, painful eye—such as glaucoma (which has a negative stain but elevated intraocular pressure) or dry eye (keratoconjunctivitis sicca, which is a leading cause of ulcers due to lack of lubricating tears).

How Deep is My Dog's Ulcer? Staging and Stroma Dynamics

Corneal ulcers are not uniform; they are staged primarily by depth and the presence of active infection or enzymatic destruction. The depth of the lesion determines the treatment protocol, the prognosis for vision, and the likelihood of surgical intervention.

Ulcer Stage	Depth & Affected Layers	Fluorescein Stain Pattern	Clinical Urgency	Primary Treatment Approach
Superficial / Simple	Epithelium loss only; stroma intact.	Solid green patch with sharp, distinct margins.	Moderate (needs prompt care but stable).	Topical prophylactic antibiotics, atropine for pain, strict E-collar.
Deep / Stromal	Penetrates into the stroma; loss of structural support.	Retained green stain with distinct depth; edges may look stepped.	High (risk of progression or scarring).	Aggressive topical antibiotics (often hourly), autologous serum, consideration of a conjunctival graft.
Melting (Keratomalacia)	Active collagenolysis; enzymes digest stroma.	Fuzzy, spreading green stain; gelatinous or slimy borders.	Extreme Emergency (can perforate in hours).	Intensive anticollagenase therapy (serum, EDTA), frequent antibiotics, systemic anti-inflammatories, surgery.
Descemetocele	Complete stromal loss; only Descemet's membrane remains.	Green "donut" ring stain; the center clear bubble does NOT stain.	Critical Emergency (imminent rupture).	Surgical stabilization (conjunctival flap, corneal graft, or amniotic transplant). Avoid touching or pressure.
Perforated Cornea	Full-thickness hole; loss of anterior chamber.	Variable; may see brown tissue (iris) plugging the hole, flat eye chamber.	Critical Emergency (sight-threatening).	Emergency surgical repair, systemic antibiotics, intraocular surgery.

The Danger of the "Melting" Ulcer (Keratomalacia)

A melting ulcer represents a rapid, destructive cascade. When bacteria (especially Pseudomonas aeruginosa or beta-hemolytic Streptococcus species) colonize a corneal wound, they release proteases and collagenases. Additionally, the dog’s own inflammatory cells (neutrophils) release matrix metalloproteinases (MMPs) to clear damaged tissue.

If this enzymatic activity is unchecked, it begins to rapidly digest the healthy collagen fibers of the stroma. The cornea loses its rigidity, takes on a soft, greyish, gelatinous appearance, and can dissolve completely within 12 to 24 hours. This is why a melting ulcer requires immediate, aggressive medical management using anticollagenases alongside potent bactericidal antibiotics.

The Descemetocele: The Green Donut

When an ulcer eats through the entire stroma, only Descemet's membrane and the single cell layer of the endothelium remain. Descemet's membrane is elastic and hydrophobic. Because it has no stroma, it does not absorb the fluorescein stain.

When a fluorescein test is performed on a descemetocele, the veterinarian will see a ring of bright green stain (representing the exposed stromal walls of the crater) surrounding a perfectly clear, dark circle in the center where the membrane is bulging forward. This is the classic "green donut" or "target sign."

A descemetocele is incredibly fragile. The pressure inside the eye (intraocular pressure) pushes the membrane outward like a tiny balloon. A single sneeze, bark, or attempt by the dog to rub its face can cause the membrane to pop, leading to a perforated eye.

When is a Corneal Ulcer an Emergency?

Every corneal ulcer requires a veterinary evaluation, but certain clinical signs indicate that the eye is actively failing or at risk of rupture, requiring an immediate trip to an emergency clinic.

       [ CLINICAL TRIAGE DECISION MATRIX ]
       
         Squinting, tearing, red eye?
                     |
         Veterinary Visit Required
                     |
      Is there any of the following?
      - Yellow-green thick discharge
      - Grayish, slimy, melting corneal surface
      - Visible dent or bulging clear bubble
      - Complete cloudiness / blue eye
      - Severe, worsening pain or whimpering
      - History of a cat scratch or penetrating wound
        /                                         \
     YES                                           NO
      |                                             |
[ EMERGENCY CLINIC ]                       [ Schedule Same-Day ]
[ Immediate Evaluation ]                   [ Next-Available Appt ]

Emergency Triggers

The Melting Appearance: If the cornea looks cloudy, grey, or has a wet, slimy, gelatinous texture around the wound, it is melting.
Purulent Discharge: A simple ulcer produces watery or slightly mucoid tearing. Thick, yellow, green, or creamy discharge indicates active bacterial infection.
The Target Sign or Defect: A visible crater, depression, or bubble on the eye surface is a sign of deep stromal loss or a descemetocele.
Cat Scratches: Any ocular injury caused by a cat claw is an automatic emergency. Cat claws are thin, curved needles contaminated with bacteria (including Pasteurella multocida). They frequently puncture the cornea, sealing bacteria deep within the stroma where topical drops cannot easily reach, leading to deep stromal abscesses.
Sudden, Intractable Pain: If a dog is on treatment but suddenly begins vocalizing, keeping the eye clamped shut constantly, or resisting head touches, the ulcer may have deepened or perforated.
Loss of the Anterior Chamber: If the eye looks "deflated," or if you can see a brown, fleshy mass (the iris) protruding through the cornea, the eye has perforated and the iris is plugging the hole to prevent total fluid loss (iris prolapse).

How a Simple Ulcer is Treated, and Why the Protocol is Rigid

For a simple, superficial corneal ulcer, the primary goals are to prevent infection, manage pain, and protect the eye from self-trauma while the epithelium heals itself. The standard protocol relies on three pillars:

1. Topical Antibiotics (Prophylaxis)

Because the exposed stroma is vulnerable to opportunistic bacteria present in the tear film, prophylactic antibiotics are prescribed.

In veterinary medicine, first-line agents include triple antibiotic ointments or drops (neomycin/polymyxin/bacitracin) and aminoglycosides like gentamicin. For infected or deep ulcers, fluoroquinolones such as ciprofloxacin and ofloxacin are utilized.

To provide context on how commonly these ophthalmic-surface drugs appear in veterinary records, we can look at spontaneous reporting patterns. The FDA's openFDA Animal & Veterinary Adverse Event API — the Center for Veterinary Medicine's spontaneous adverse-event reporting system — records the following report counts for these active ingredients across veterinary cases:

Atropine: 680 reports
Ciprofloxacin: 192 reports (plus Ciprofloxacin HCl: 88 reports, totaling 280)
Ofloxacin: 133 reports
Erythromycin: 87 reports

These numbers reflect spontaneous reports associated with these ingredients, highlighting their ubiquitous use on the ocular surface and adjacent clinical pathways. For a simple ulcer, topical drops are typically applied 3 to 4 times daily. If an infection is active or the ulcer is deep, this frequency may increase to every 1 to 2 hours.

2. Atropine (Pain Control and Synechiae Prevention)

Corneal ulcers are incredibly painful because the cornea is one of the most densely innervated tissues in the body, packed with sensory fibers from the ophthalmic branch of the trigeminal nerve.

This sensory irritation triggers a reflex spasm of the ciliary body muscle and the pupillary sphincter muscle inside the eye. This muscle spasm is what causes the deep, aching pain, squinting, and constricted pupil (miosis) associated with ulcers.

Topical Atropine Sulfate (1%) is a potent anticholinergic agent that performs two vital tasks:

Cycloplegia: It paralyzes the ciliary muscle, resolving the painful muscle spasms.
Mydriasis: It dilates the pupil. Dilation keeps the iris away from the anterior lens surface, preventing the iris from sticking to the lens (posterior synechiae) during active intraocular inflammation (reflex uveitis).

Crucial Cautions with Atropine:

Bitter Taste & Salivation: Atropine is extremely bitter. In dogs, the tear ducts drain into the nasal passages and then into the throat. When atropine drops drain through the nasolacrimal duct, the dog will taste the drug, leading to profuse foaming at the mouth, drooling, and head shaking. This is a common physiological reaction, not an allergic reaction. Owners can mitigate this by applying a clean tissue to the corner of the eye for 30 seconds after administration to absorb excess fluid.
Photophobia: Because the pupil is widely dilated, the dog's eye cannot constrict to limit light. Keep the dog out of bright sunlight during atropine therapy.
Decreased Tear Production: Atropine can temporarily decrease aqueous tear production. If the dog has pre-existing dry eye, use atropine cautiously and monitor tear levels.

3. The Elizabethan Collar (The Cone): Non-Negotiable Protection

It is impossible to overstate the importance of the cone. A dog experiencing eye pain has a natural instinct to rub its face against carpets, furniture, or use its paws to scratch the eye.

The cornea of an ulcerated eye is structurally compromised. A single rub can convert a simple, superficial scratch into a deep, infected stromal tear, or cause a descemetocele to rupture instantly.

The cone must remain on 24 hours a day, 7 days a week, until the veterinarian confirms the eye is fully healed. Soft fabric collars or inflatable "donut" collars are contraindicated for eye injuries because they do not prevent a dog from bending their neck to rub their face against the corner of a table or the carpet. A rigid, plastic, classic Elizabethan collar is the only effective barrier.

Never Stop Drops Before the Recheck

A common mistake owners make is stopping treatment once the dog stops squinting and the eye looks clear.

The corneal epithelium can slide over a wound and cover it within days, but the cellular anchors (hemidesmosomes) that bind the new epithelium to the underlying stroma take several weeks to mature and secure the tissue.

If treatment is stopped prematurely, or if the cone is removed too early, the fragile new cell sheet can easily peel off, causing the ulcer to recur. Always return for the scheduled recheck, where the veterinarian will perform a repeat fluorescein stain to verify that the epithelial barrier is structurally complete and stain-negative.

Indolent (Non-Healing) Ulcers: The Boxer Ulcer

Sometimes, a superficial corneal ulcer fails to heal despite weeks of appropriate antibiotic therapy, pain management, and strict cone compliance. If a superficial ulcer has not resolved within 7 to 10 days, it is classified as an indolent ulcer, medically referred to as a Spontaneous Chronic Corneal Epithelial Defect (SCCED).

       [ SCCED PATHOPHYSIOLOGY ]
       
Normal Healing:
============================== (Epithelium)
   ||||||  <- Hemidesmosome anchors secure cells
------------------------------ (Basement Membrane & Stroma)

SCCED (Indolent Ulcer):
   ====      ====  <- Detached epithelial "lips"
  /    \    /    \
============================== (Epithelium fails to anchor)
============================== (Abnormal Hyaline Zone in Stroma)
------------------------------ (No cellular adhesion)

Why SCCEDs Occur

An indolent ulcer is not caused by an active infection. Instead, it is a structural failure of cellular adhesion.

Affected dogs develop an abnormal, acellular hyaline zone in the superficial stroma, and their basement membrane fails to produce the normal hemidesmosomal anchors that lock epithelial cells to the underlying tissue.

As a result, new epithelial cells migrate to cover the wound, but they cannot stick. They remain loose, forming fragile, unattached "lips" or sheets of cells that slide around, fluid pools underneath them, and the ulcer remains open indefinitely.

SCCEDs are most common in middle-aged and older dogs, with a strong breed predisposition in Boxers (often called the "Boxer ulcer"), Corgis, French Bulldogs, Boston Terriers, and Golden Retrievers.

The Procedural Ladder for Indolent Ulcers

Because drops alone cannot fix the underlying adhesion defect, a clinical procedure is required to remove the abnormal tissue and stimulate healing. Vets follow a structured management ladder:

1. Epithelial Debridement (Cotton-Tip Debridement)

Using topical anesthesia (proparacaine drops), the veterinarian uses sterile, dry, cotton-tipped applicators to gently rub the surface of the cornea.

All normal, healthy epithelial cells will resist the rubbing and stay in place. However, the loose, unanchored epithelial lips of the SCCED will peel away easily.

This debridement is performed outward from the center of the wound until a clean, firmly attached border of epithelial cells is reached. This removes the non-viable cells that were blocking new cells from migrating across the stroma. Debridement alone has a success rate of approximately 40% to 50%.

2. Diamond Burr Debridement (DBD)

If simple debridement fails, or as a primary treatment, vets use a handheld, battery-powered tool equipped with a tiny rotating tip covered in diamond dust (a diamond burr).

After numbing the eye, the surgeon lightly polishes the exposed stroma. The rotating diamond burr gently removes the abnormal hyaline zone in the superficial stroma without penetrating deep into the tissue.

This creates a micro-abrasive, clean surface that allows migrating epithelial cells to form new, stable anchors. DBD has a high success rate (85% to 90% healing within two weeks) and is widely considered the gold standard for managing canine SCCEDs in general practice.

3. Grid Keratotomy

In cases where a diamond burr is unavailable, a veterinarian may perform a grid keratotomy. Under topical anesthesia, a fine-gauge sterile needle is used to draw a grid pattern of shallow, superficial scratches across the exposed stroma and slightly into the healthy epithelial margins.

Like the diamond burr, this micro-trauma disrupts the abnormal hyaline barrier and exposes healthy stromal collagen, providing anchor points for migrating cells.

Grid keratotomies must only be performed on indolent (SCCED) ulcers. They are strictly contraindicated in cats (where they can cause feline corneal sequestrum formation) and in any dog with a deep, infected, or melting ulcer (where the needle scratches would worsen the structural damage or spread infection).

Advanced Ophthalmic Therapies

For deep, melting, or refractory corneal ulcers, veterinary ophthalmologists utilize advanced biological and physical therapies to arrest tissue destruction and facilitate repair:

Autologous Serum Therapy

Autologous serum is prepared by drawing a blood sample from the patient (or a donor dog), spinning it down in a centrifuge, and separating the liquid serum. The serum is then placed in sterile dropper bottles and kept refrigerated.

Serum is a potent biological therapy because it contains high concentrations of alpha-2 macroglobulins, alpha-1 antitrypsin, and other antiproteases. These natural proteins bind to and neutralize the collagenases and matrix metalloproteinases (MMPs) that drive melting ulcers.

Additionally, serum contains epithelial growth factors that promote cellular migration and repair. Serum drops must be applied frequently (every 1 to 2 hours) in the early stages of keratomalacia.

Corneal Collagen Cross-Linking (CXL)

Adapted from human ophthalmology, CXL is an emerging veterinary therapy for infectious and melting keratitis. The procedure involves applying topical Riboflavin (Vitamin B2) drops to the cornea until it penetrates the stroma, then exposing the eye to a calibrated dose of Ultraviolet-A (UVA) light.

The UVA light excites the riboflavin, creating reactive oxygen species that induce covalent bonds to form between adjacent collagen fibrils in the stroma. This significantly increases the mechanical strength of the cornea, making it highly resistant to enzymatic digestion by bacterial and neutrophil collagenases.

Furthermore, the combination of riboflavin and UVA light has a direct, potent bactericidal effect, helping to sterilize the corneal surface.

Breed Predispositions and Predisposing Causes

While any dog can scratch their eye, certain breeds are at a massively increased risk of developing corneal ulcers due to their facial anatomy.

       [ BRACHYCEPHALIC COMPROMISE SHIELD ]
       
              Exophthalmos (bulging eyes)
                         |
           Lagophthalmos (incomplete blink)
                         |
             Central Tear Film Desiccation
                         |
         Decreased Corneal Sensitivity (trigeminal)
                         |
          [ High Vulnerability to Ulceration ]

The Brachycephalic Risk

Brachycephalic breeds—dogs with shortened muzzles, such as Pugs, Shih Tzus, Pekingese, French Bulldogs, and Boston Terriers—possess a combination of anatomical traits that compromise corneal safety:

Exophthalmos: Shallow bony orbits cause the eyeballs to bulge forward, leaving more corneal surface area exposed to wind, dust, and physical trauma.
Macropalpebral Fissure: Oversized eyelid openings prevent complete closure of the eyelids during blinking (lagophthalmos), leading to chronic dry spots and exposure keratitis in the center of the eye.
Medial Entropion: The inner corners of the eyelids roll inward, causing the facial hair near the nose to constantly rub against the cornea (trichiasis).
Decreased Corneal Sensitivity: Brachycephalic dogs have fewer sensory nerve endings in the central cornea than dolichocephalic (long-nosed) dogs. Because they do not feel minor corneal irritation, they do not blink or tear reflexively in response to wind or debris, allowing minor abrasions to go unnoticed until they become deep ulcers.

Upstream Causes and Co-Morbidities

Before an ulcer can heal permanently, any underlying predisposing factors must be addressed:

Keratoconjunctivitis Sicca (KCS / Dry Eye): A lack of adequate aqueous tear production leads to friction between the eyelid and the cornea, causing chronic micro-abrasions. Any dog diagnosed with an ulcer should undergo a Schirmer Tear Test (unless a descemetocele is present) to rule out KCS.
Eyelid Conformation Disorders: Entropion (inward-rolling lids), ectropion (outward-sagging lids), distichiasis (extra eyelashes growing from the gland openings), and ectopic cilia (hairs growing straight through the inner conjunctiva of the lid) mechanically abrade the cornea with every blink. These structural abnormalities require surgical correction to prevent recurrent ulceration. For details on structural causes, see our guide to canine conformational eyelid disorders.

FAQs: Canine Corneal Ulcers

How long does a corneal ulcer take to heal in a dog?

A simple, superficial corneal ulcer that is protected from self-trauma and receives appropriate prophylactic drops typically heals within 5 to 7 days. The corneal epithelium is one of the fastest-healing tissues in the body, with cells migrating rapidly to cover the defect. If an ulcer has not healed within 7 to 10 days, it is likely complicated by a non-healing structure (indolent ulcer), an underlying infection, dry eye, or mechanical irritation (such as an eyelash rubbing the eye).

Yes. If an ulcer is deep or becomes infected by bacteria that release collagen-destroying enzymes (a melting ulcer), the erosion can rapidly progress through the stroma. Once the final thin layer (Descemet's membrane) ruptures, the fluid inside the eye escapes, causing the eye to collapse. This can lead to severe intraocular infection (endophthalmitis) or glaucoma, which frequently requires surgical removal of the eye (enucleation) to relieve pain. Prompt veterinary intervention and strict compliance are essential to preserve vision. (If the cloudiness you are seeing is inside the lens rather than on the surface, that is a different problem — see our guide to cataracts in dogs.)

Why does my dog need an Elizabethan collar (cone) for an eye ulcer?

Dogs cannot comprehend that rubbing an injured eye will make it worse; they only feel pain and irritation. A dog will attempt to relieve this discomfort by scratching the eye with their dewclaws or rubbing their face along rugs and furniture. Because the cornea is weakened by the ulcer, a single episode of rubbing can tear the stroma, introduce bacteria, or cause the eye to rupture. Soft fabric collars or inflatable donuts are not rigid enough to stop a dog from rubbing their face against protruding objects. A rigid plastic cone is the only reliable way to protect the eye.

What happens if I stop the eye drops before the recheck?

Stopping medication early is a leading cause of ulcer recurrence. While the superficial cells may migrate to cover the wound quickly, the cellular anchors that lock the new epithelium to the underlying stroma take several weeks to form. If you stop the drops or remove the cone before a veterinarian performs a repeat fluorescein stain and confirms complete healing, the new epithelial layer can easily peel away, reopening the ulcer and restarting the healing process.

Are brachycephalic breeds (Pugs, French Bulldogs, Shih Tzus) at higher risk?

Yes. Brachycephalic dogs have flat faces, shallow eye sockets, and bulging eyes, which leaves a larger surface of the cornea exposed to injury. Many also suffer from lagophthalmos (an inability to blink completely over the center of the eye) and medial entropion (eyelids rolling inward near the nose, causing hair to rub the eye). Additionally, their corneas have less nerve sensitivity, meaning they do not blink or tear reflexively when their eye is irritated, making them highly prone to severe, deep ulcers from minor injuries.

Sources

Today's Veterinary Nurse: Managing Canine Corneal Ulcers: Diagnostics, Staging, and Treatment Strategies. URL: https://todaysveterinarynurse.com/ophthalmology/managing-canine-corneal-ulcers
VCA Animal Hospitals: Corneal Ulcers in Dogs: Cause, Signs, and Treatment. URL: https://vcahospitals.com/know-your-pet/corneal-ulcers-in-dogs
University of Tennessee College of Veterinary Medicine (UTCVM): Ophthalmology Service: Indolent Corneal Ulcers in Dogs FAQs. URL: https://vetmed.tennessee.edu/wp-content/uploads/sites/4/UTCVM_Ophthalmology-IndolentUlcers-In-Dogs_FAQs.pdf
Today's Veterinary Practice: Corneal Ulcers: A Pet Owner's Guide. URL: https://todaysveterinarypractice.com/pet-owner-resources/sentrx-corneal-ulcers-handout
U.S. Food and Drug Administration (FDA): openFDA Animal & Veterinary Adverse Event API (Center for Veterinary Medicine adverse-event reporting system). URL: https://api.fda.gov/animalandveterinary/event.json

Vet Med Guide

Corneal Ulcers in Dogs: Diagnostic Staging, Treatment, and Cone Rules