Chemicals in the Eye (Eye Burns)
A chemical burn to the eye represents a serious injury where chemical substances come into contact with and damage the sensitive tissues of the eye. The eyes of dogs and cats consist of various highly sensitive structures that can be quickly and permanently damaged when in contact with corrosive substances. The cornea, conjunctiva, and sclera are particularly at risk as they form the outer protective layers of the eye and are thus the first to come into contact with chemicals.
The severity of a chemical burn is largely determined by three factors: the type of chemical, its concentration, and the duration of exposure. Particularly problematic are alkalis (alkaline substances), as they penetrate deeper into the tissue than acids and thus often cause more severe damage. While acids cause coagulation necrosis on the surface, which limits further penetration, alkalis lead to liquefaction necrosis, allowing deeper penetration and thus potentially having more serious long-term consequences.
Causes
Eye burns in pets occur through contact with various chemical substances found in households, gardens, or garages. The most common causes can be categorized as follows:
Alkaline substances (bases) represent the most dangerous group. These include cleaning agents such as drain cleaners, oven and grill cleaners, laundry detergents, ammonia compounds, and construction chemicals like cement, lime, and concrete. These substances have a pH value above 7 and can penetrate particularly deep into eye tissue as they liquefy proteins and fats.
Acidic substances with a pH value below 7 include battery acid, rust removers, pool chemicals, toilet cleaners, and certain fruit vinegars in high concentrations. Although acids tend to cause more superficial damage than bases, they can still cause significant injuries.
Organic solvents such as gasoline, turpentine, nail polish remover, and antifreeze remove fats from the tissue and can thereby destroy the lipid layer of the cornea. This leads to increased permeability for other harmful substances.
For dogs and cats, there are additional breed-specific risks. Brachycephalic (short-headed) breeds such as Pugs, French Bulldogs, or Persian cats have anatomically protruding eyes that are less protected by the eye socket and thus exposed to a higher risk of injury. Additionally, behavioral factors such as sniffing in trash containers or exploring garages and workshops can increase the risk of eye burns.
Symptoms
- Severe pain
- Visual impairment up to loss of vision
- Increased blood flow to the conjunctiva or
- Pale conjunctiva due to destruction of blood vessels and consequently reduced blood flow to the region
- Edema of the eyelids and/or conjunctiva
- Spasmodic closing of the eyelids (blepharospasm)
- Corneal clouding (fish eye)
The symptoms of eye burns in dogs and cats usually occur immediately after contact with the damaging substance and can vary depending on the severity and type of chemical. Characteristic signs include:
Acute pain expressions are often the first noticeable symptom. Affected animals show restlessness, howling or whining, and try to rub their eye with their paws. Spasmodic closing of the eyelids (blepharospasm) occurs as a protective reaction and can be so severe that the animal can hardly open its eye.
The conjunctiva reacts with strong redness (hyperemia) due to increased blood flow. In very severe burns, however, a pale conjunctiva can also occur if the blood vessels have already been destroyed. Increased tear production (epiphora) is another attempt by the body to flush out the damaging substance.
Various changes can be observed on the cornea. Corneal clouding (also referred to as “fish eye”) occurs due to damage to the normally transparent corneal tissue. In severe burns, corneal erosions or even ulcerations (deeper defects) can occur. In advanced cases, perforation of the cornea can happen.
The eyelids and conjunctiva can swell significantly (edema), and in severe cases, tissue necrosis can occur. Impairment of vision up to complete loss of sight is possible, with the animal showing signs such as unsteady walking or bumping into objects.
In cats and dogs, the symptoms may differ slightly. Cats tend to withdraw and hide their discomfort when experiencing eye pain, while dogs more often show obvious pain reactions. Therefore, special attention is required to detect eye burns early in cats.
First Aid
- If chemicals have entered the eyes, rinse the affected eye as quickly as possible, for a very long time (at least 15 minutes) under running, lukewarm or cold water. In an emergency, non-alcoholic beverages can also be used.
- Exception: Do not rinse if lime has entered the eye. This must be removed mechanically. Rinsing with water would create a strongly corrosive lye, which in turn would cause severe damage.
- Try to open the eyelids. If your pet is not cooperative, still try to rinse, even if you have to compromise on thoroughness.
- Try to rinse near the eye so that the water at least runs over the eyes.
- Turn the animal’s head so that the affected eye is lower, preventing the rinsing fluid from flowing into the healthy eye.
- However, do not rub.
- Do not use any eye medications without the recommendation of a veterinarian.
- Take the container of the chemical with you or write down the text on the label.
Diagnosis
The diagnosis of an eye burn is made through a thorough ophthalmological examination, ideally performed by a veterinarian experienced in veterinary ophthalmology. As this is an emergency, a medical history is first taken, during which the pet owner is asked about possible contact with chemicals. Information about the type of chemical is particularly valuable, which is why pet owners should bring the container of the suspected substance to the veterinary examination.
The clinical examination begins with a careful inspection of the eye area and visible eye structures. Due to the pain, local anesthesia through eye drops is often necessary to enable a detailed examination. A slit lamp is used to closely examine the anterior eye segments to assess the extent of damage.
A fluorescein staining test is performed to assess corneal integrity. Damaged corneal tissue absorbs the dye and appears green under blue light, making defects visible. If deeper damage is suspected, tonometry may be performed to measure intraocular pressure, as burns can lead to pressure changes.
Determining the pH value of the eye surface using special test strips can provide clues about the type of corrosive substance and is particularly important when the causing chemical is unknown. Deviations from the physiological pH of the eye (about 7.4) indicate remaining corrosive substances.
In severe burns, further imaging such as ultrasound or OCT (Optical Coherence Tomography) may be necessary to fully assess the extent of damage, especially if deeper eye structures might be affected.
Further veterinary measures
Take your pet to a veterinarian immediately. Chemical burns to the eye are an ophthalmic emergency!
The treatment of chemical eye burns in dogs and cats requires a quick and systematic approach. Ideally, first aid begins with the pet owner immediately and extensively rinsing the affected eye. This should be done with plenty of lukewarm water or physiological saline solution for at least 15-20 minutes. It is important to position the animal’s head so that the rinsing fluid flows from the affected eye to the unaffected eye to avoid contamination of the healthy eye.
In the veterinary practice, the rinsing is intensified and continued under controlled conditions. Special eye rinsing solutions with a physiological pH value are used here. For burns caused by alkalis, a longer rinsing of up to 60 minutes may be necessary, as these penetrate deeper into the tissue. After rinsing, the pH value of the eye surface is checked and rinsing is continued if necessary until a physiological value is reached.
The medication therapy includes several components: Topical antibiotics in the form of eye drops or ointments serve as infection prophylaxis, as the damaged cornea is more susceptible to bacterial infections. Broad-spectrum antibiotics such as ofloxacin or chloramphenicol are often used. For pain relief and anti-inflammatory effects, non-steroidal anti-inflammatory drugs (NSAIDs) are administered locally and systemically. In severe burns, corticosteroids may also be used under strict veterinary supervision to dampen the inflammatory response.
To support corneal healing, artificial tears and, if necessary, collagenase inhibitors are used to slow down the breakdown of corneal tissue. For deeper corneal defects, special bandage contact lenses or temporary third eyelid flaps may be applied to promote healing.
In severe cases with corneal perforation or extensive tissue destruction, surgical interventions such as conjunctival flaps, corneal transplants, or, as a last resort, even enucleation (removal of the eyeball) may be necessary.
Prognosis and aftercare
The prognosis for eye chemical burns depends significantly on several factors: the type and concentration of the causative substance, the duration of exposure, the speed of initial care, and the extent of initial tissue damage. Generally, the earlier the flushing and veterinary treatment occurs, the better the chances of healing. Alkali burns often have a poorer prognosis than acid burns due to their deeper tissue penetration.
For superficial burns with prompt treatment, the prognosis is usually good, and complete restoration of vision is possible. In moderate burns, corneal scars may remain, which, depending on their location and extent, can impair vision. Severe burns involving deeper eye structures can lead to permanent visual impairments or even loss of the eye despite intensive therapy.
Aftercare includes regular veterinary check-ups, initially daily, later at longer intervals. Medication must be administered strictly according to veterinary instructions, with the application frequency adjusted as healing progresses. Particularly important is the consistent application of eye drops and ointments, which often must be continued for several weeks.
To protect against self-injury, wearing an Elizabethan collar may be necessary. The animal’s environment should be arranged to minimize injury risks, for example, by removing obstacles in case of impaired vision.
Long-term complications that can occur after an eye chemical burn include chronic keratitis (inflammation of the cornea), symblepharon (adhesions between the conjunctiva and cornea), glaucoma (increased intraocular pressure), and cataracts (lens opacity). These require continuous veterinary monitoring and, if necessary, adjusted therapy.
Summary
Eye chemical burns in dogs and cats constitute a medical emergency that requires immediate action. They occur through contact with corrosive substances such as alkalis, acids, or organic solvents, which are contained in many household, garden, and car care products. The damage to the eye tissue can range from superficial irritation to profound, vision-threatening injuries, depending on the type of chemical, concentration, and duration of exposure.
The clinical signs include pain, blepharospasm, redness, swelling, increased tear flow, and corneal opacity. The diagnosis is made through a thorough ophthalmological examination, with the fluorescein test and pH value determination being important diagnostic tools.
Treatment begins with extensive flushing of the eye, followed by medical treatment with antibiotics, pain relievers, and anti-inflammatory substances. In severe cases, surgical interventions may be necessary. The prognosis depends on the severity of the burn and the speed of treatment, with early intervention significantly improving the chances of healing.
Aftercare includes regular veterinary check-ups and consistent application of prescribed medications. Preventive measures such as safe storage of chemicals and the use of protective equipment when working with potentially dangerous substances are crucial to avoid eye burns in pets.
Outlook on current research
Research in the field of treating eye burns in small animals continues to evolve. Current studies focus on innovative therapeutic approaches aimed at promoting healing and minimizing long-term damage. A promising area is regenerative medicine using stem cells for corneal regeneration. Mesenchymal stem cells have shown in experimental studies that they can accelerate corneal repair and reduce scarring.
Advances in biomaterial research have led to the development of new materials for corneal implants. Synthetic collagen matrices and biocompatible polymers offer alternatives to traditional transplants and can serve as scaffolds for tissue regeneration. These materials are increasingly being used in veterinary ophthalmology as well.
The development of special eye irrigation solutions with chelating agents specifically tailored to certain chemicals could improve initial care. These solutions neutralize the corrosive substance more effectively than conventional rinses and can thus reduce the extent of tissue damage.
Advances in topical drug administration through novel formulations such as hydrogels or nanoparticles allow for longer residence time and better penetration of active ingredients in the eye. This could improve therapy adherence and optimize healing outcomes.
The advancement of diagnostic imaging techniques such as high-resolution OCT (Optical Coherence Tomography) enables more precise assessment of tissue damage and better therapy planning. These non-invasive procedures allow for detailed imaging of corneal layers and can accurately document the healing process.
Frequently asked questions (FAQs)
- Which household chemicals are particularly dangerous for my pet’s eyes?
Particularly dangerous are strongly alkaline products such as drain cleaners, oven cleaners, and concentrated laundry detergents. Battery acid, pool chemicals, and concentrated cleaning agents also pose a high risk. - How can I tell if my pet has suffered a chemical eye burn?
Typical signs include sudden eye rubbing, excessive blinking, blepharospasm, redness, swelling, increased tearing, and possibly visible clouding of the cornea. The animal shows clear signs of pain and avoids bright light. - What is the difference between a burn caused by acids and alkalis?
Acids typically cause more superficial damage as they produce coagulation necrosis, which limits further penetration. Alkalis, on the other hand, lead to liquefaction necrosis, penetrate deeper into the tissue, and often cause more severe long-term damage. - Is tap water suitable for initial rinsing in case of a chemical eye burn?
Yes, in an emergency, tap water is suitable for immediate rinsing. The most important thing is to act quickly to dilute and flush out the corrosive substance. Ideally, lukewarm water should be used. - How long does healing take after a chemical eye burn?
The healing time varies depending on the severity of the burn. Mild superficial burns can heal within 1-2 weeks, while moderate to severe burns may take several weeks to months and can leave permanent damage. - Can my pet regain full vision after a chemical eye burn?
With mild to moderate chemical burns and prompt treatment, a complete restoration of vision is possible. However, severe chemical burns can lead to permanent visual impairments or even loss of vision. - What preventive measures can I take to avoid eye chemical burns in my pet?
Store all chemicals in locked cabinets, use childproof locks, don’t leave open containers with chemicals unattended, and keep your pets away when working with potentially dangerous substances. - Are certain dog or cat breeds more susceptible to eye chemical burns?
Brachycephalic (short-headed) breeds such as Pugs, French Bulldogs, or Persian cats have anatomically protruding eyes that are less protected by the eye socket and may therefore be at higher risk. - How often should eye drops be applied after a chemical burn?
The frequency of application is determined individually by the veterinarian and depends on the severity of the chemical burn. In the acute phase, eye drops may be required every 1-2 hours, later the frequency is reduced. - Can an untreated eye chemical burn lead to the loss of the eye?
Yes, without adequate and timely treatment, a severe eye chemical burn can lead to irreversible damage that may necessitate enucleation (surgical removal of the eye).
Literature
- https://www.augenaerzte-aarau.ch/veraetzungen-der-augen/
- Löwe, G. and Löwe, O., 2021. Emergencies in Dogs and Cats – A Veterinary Guide. Kreuztal: Kynos-Verlag.
- Merck & Co., 2020. Merck Veterinary Manual. 11th Edition. Kenilworth: Merck Publishing.
- Ledbetter, E.C. and Gilger, B.C. (2021). Diseases and Surgery of the Canine Cornea and Sclera. In: Gelatt, K.N., Ben-Shlomo, G., Gilger, B.C., Hendrix, D.V.H., Kern, T.J. and Plummer, C.E. (Eds.) Veterinary Ophthalmology. 6th Edition. Hoboken: Wiley-Blackwell, pp. 1082-1164.
- Esson, D.W. (2020). Clinical Atlas of Canine and Feline Ophthalmic Disease. Hoboken: Wiley-Blackwell.
- Schrage, N. and Struck, H.G. (2016). Guideline for the Treatment of Chemical and Thermal Burns of the Eyes and Eyelids / Chemical and Thermal Burns of the Eyes: Treatment Recommendations. Association of the Scientific Medical Societies in Germany (AWMF).