Bleeding on the Eyeball and around the Eye
A bloody eye in pets refers to various forms of bleeding that can occur in or around the eye. These hemorrhages can affect different structures of the eye and vary in severity and clinical significance. The anatomical features of the eye in dogs and cats play an important role in understanding these conditions.
Our pets’ eyes consist of various structures that can be affected by hemorrhages: the conjunctiva, the anterior chamber, the vitreous body, the retina, and the structures around the eye, including the eyelids and the orbit (eye socket). Depending on the affected structure, we distinguish between different types of eye hemorrhages, which have different causes, symptoms, and treatment approaches.
There are anatomical differences in the structure of the eye in dogs and cats that can influence the occurrence and course of eye hemorrhages. Cats have the tapetum lucidum, a reflective layer behind the retina, which can be affected differently by hemorrhages than in dogs. Additionally, brachycephalic (short-headed) dog and cat breeds like Pugs, French Bulldogs, or Persian cats have an increased risk of certain eye problems due to their skull structure, as their eyes often protrude more (exophthalmos) and are thus more susceptible to injuries.
Causes
The causes of eye bleeding in pets are diverse and can be divided into traumatic causes, systemic diseases, and primary eye diseases.
Traumatic causes are particularly common and include blunt trauma from collisions, falls, or blows, which can lead to bleeding under the conjunctiva (subconjunctival hemorrhage) or in the eye chamber (hyphema). Foreign bodies in the eye, scratch injuries from other animals or plant parts, and bite wounds can also cause bleeding. In cats, scratch injuries from other cats are a common cause of eye bleeding.
Bleeding under the conjunctiva of the eye, even if it affects the entire eyeball, is painless and does not require treatment. It does not impair vision. These also occur due to injuries to small blood vessels in the conjunctiva.
On the other hand, a serious injury may be present, especially if bleeding has also occurred inside the eye.
A bone fracture near the eye or even a skull fracture can lead to severe subcutaneous bleeding in the eye region. In the case of a skull fracture, both eye regions can be affected simultaneously. This creates a “spectacle formation” around the eyes (monocle hematoma or raccoon eyes). In such cases, blood often also comes out of the nose.
Bleeding inside the bony eye socket behind the eyeball can lead to severe swelling, causing the eyeball to be pushed forward and possibly preventing the eyelids from closing.
In systemic diseases, high blood pressure is particularly prominent, which often occurs in older cats with kidney diseases and can lead to retinal bleeding. Blood clotting disorders, whether due to genetic factors such as von Willebrand’s disease in dogs or acquired through poisoning (e.g., with rat poison), can also promote eye bleeding. Infectious diseases such as leptospirosis in dogs or feline leukemia virus (FeLV) in cats can be associated with eye bleeding. Autoimmune diseases such as systemic lupus erythematosus can lead to inflammation of the blood vessels (vasculitis), which can result in bleeding.
Primary eye diseases such as glaucoma (increased intraocular pressure) can lead to vessel ruptures and bleeding due to increased pressure. Uveitis (inflammation of the middle layer of the eye) can be associated with bleeding in the anterior chamber of the eye. Retinal detachments are often associated with bleeding, and tumors in or around the eye can lead to bleeding due to abnormal vessel formation or tissue destruction.
The causes differ partly between dogs and cats. In cats, hypertensive retinopathies due to high blood pressure are particularly common, while in dogs, traumatic causes and coagulation disorders are more prominent.
Symptoms
The symptoms of a bloody eye vary depending on the type, location, and severity of the bleeding. Careful observation of these symptoms is important for pet owners to assess the urgency of a veterinary visit.
In subconjunctival hemorrhages, the conjunctiva appears light red to dark red, with the bleeding being diffuse or punctate. These hemorrhages are usually painless and do not affect vision. The animal typically shows no behavioral changes, and the bleeding can affect the entire visible part of the eyeball or just a portion of it.
A hyphema, which is blood in the anterior chamber of the eye, appears as a reddish discoloration behind the cornea, which can partially or completely obscure the iris depending on the severity. Affected animals often show signs of pain such as increased blinking, tearing, or light sensitivity. Vision may be impaired, which can manifest as more cautious movements or bumping into objects.
Bleeding in the vitreous or retina is often not directly visible from the outside but can lead to sudden vision disturbances. Affected animals may appear disoriented, walk into objects, or have difficulty jumping. In cases of extensive retinal bleeding, pupil dilation that does not respond to light may occur.
Bleeding in the eye socket (orbital hemorrhage) leads to protrusion of the eyeball (exophthalmos) and can be accompanied by swelling of the surrounding tissues. The eyelids may be swollen and possibly unable to close completely. These hemorrhages are often painful and can lead to fever and general discomfort.
In traumatic injuries, additional symptoms such as bruising around the eye (“black eye”), swelling of the eyelids, or corneal injuries may occur. In severe trauma, “raccoon eyes” (periorbital ecchymosis) may develop around both eyes, especially if a skull fracture is present. In such cases, blood often also comes out of the nose.
First Aid
- Cooling with cold compresses helps to stop bleeding under the skin and reduce swelling.
- Cooling should be applied as soon as possible after the injury. However, no pressure should ever be applied to the eyeballs themselves.
- Repeated cooling is beneficial for the next 24 hours.
- After two days, local heat application (compresses) helps to reduce the bruising.
Diagnosis
The diagnosis of eye hemorrhages requires a thorough ophthalmological examination and, if necessary, further diagnostic procedures to determine the cause and extent of the bleeding.
The clinical examination begins with a general assessment of the animal, followed by a targeted examination of the eye and its surrounding area. The veterinarian looks for signs of trauma, swelling, or asymmetries between both eyes. With a slit lamp, the anterior segments of the eye can be examined in detail to assess subconjunctival hemorrhages or hyphema.
Ophthalmoscopy (examination with an ophthalmoscope) allows for the assessment of the eye fundus and can reveal retinal hemorrhages, retinal detachments, or changes in blood vessels. This examination is particularly important for cats suspected of having high blood pressure, as hypertensive retinopathies often lead to retinal hemorrhages.
Tonometry (measurement of intraocular pressure) is important to rule out or confirm glaucoma as a cause or consequence of the bleeding. Increased intraocular pressure can be both a cause and a result of eye hemorrhages and requires immediate treatment.
Imaging techniques such as ultrasound of the eye are particularly valuable when the transparency of the ocular media is limited by bleeding and a direct assessment of the eye fundus is not possible. If orbital hemorrhages or skull fractures are suspected, computed tomography (CT) or magnetic resonance imaging (MRI) may be necessary.
Laboratory tests include a complete blood count, coagulation parameters, and biochemical profiles to identify systemic causes such as blood clotting disorders, infections, or organ diseases. For cats suspected of having high blood pressure, blood pressure measurement is essential, ideally in a calm environment to minimize stress-related distortions.
The diagnosis must differentiate between various types of eye hemorrhages and identify their causes to enable targeted treatment.
Further veterinary measures
The treatment of eye bleeding depends on the cause, the extent of the bleeding, and the affected structures of the eye. It includes both first aid measures and specific veterinary treatments.
As a first aid measure for traumatic eye bleeding, cooling with cold compresses is helpful to stop the bleeding and reduce swelling. This should begin as soon as possible after the injury, taking care never to apply pressure to the eyeball itself. Cooling can be repeated at regular intervals for the first 24 hours. After about two days, local heat application can promote the breakdown of the bruise.
For subconjunctival hemorrhages that do not show any further complications, specific treatment is often not necessary, as they usually resorb on their own within 1-2 weeks. However, the veterinarian may prescribe artificial tears to moisturize the eye and protect it from irritation.
A hyphema requires more intensive treatment. Medicinal therapies include anti-inflammatory eye drops (corticosteroids or non-steroidal anti-inflammatory drugs) to reduce inflammation, as well as pupil-dilating agents (mydriatics) to prevent adhesions between the iris and lens. If intraocular pressure is elevated, medications to lower blood pressure are used.
In cases of severe bleeding, especially when associated with trauma or glaucoma, inpatient treatment with intravenous medications may be necessary. In some cases, surgical intervention may be required to remove blood from the anterior chamber of the eye (paracentesis) or repair other structures.
The treatment of systemic underlying diseases is crucial for long-term success. For cats with high blood pressure, blood pressure-lowering medications such as calcium channel blockers (e.g., amlodipine) or ACE inhibitors are used. In cases of coagulation disorders, substitution therapy with coagulation factors or vitamin K may be necessary.
In severe eye injuries with extensive bleeding that has led to irreversible damage, in some cases, removal of the eye (enucleation) may be the best option to spare the animal pain and prevent the spread of infections.
Prognosis and aftercare
The prognosis for eye hemorrhages depends significantly on the cause, extent of bleeding, affected structures, and speed of treatment. Careful follow-up care is crucial for long-term treatment success.
For superficial subconjunctival hemorrhages, the prognosis is usually excellent. These hemorrhages typically resorb completely within 1-2 weeks without leaving permanent damage. Regular check-ups by a veterinarian are still important to ensure that no deeper problems have been overlooked.
With a hyphema, the prognosis should be approached more cautiously. Minor bleeding in the anterior chamber can fully resolve if treated early and appropriately. In cases of massive bleeding or if blood remains in the eye chamber for an extended period, there is a risk of complications such as glaucoma, synechiae (adhesions of the iris), or corneal damage, which can permanently impair vision.
The prognosis for retinal hemorrhages varies. Small, pinpoint bleedings can heal without permanent damage, while extensive hemorrhages can lead to scarring and permanent vision impairment. In cats with hypertensive retinopathy, vision can be partially restored if high blood pressure is quickly controlled.
Follow-up care includes regular check-ups with the veterinarian to monitor the healing process and detect potential complications early. Depending on the cause of the bleeding, these check-ups may occur at short intervals (initially daily or weekly) or over longer periods (monthly or quarterly).
Home monitoring by the pet owner is an important part of follow-up care. Pet owners should watch for signs of deterioration, such as increasing redness, swelling, discharge, pain, or behavioral changes that could indicate vision problems. Photo documentation of the healing process can be helpful to objectively assess changes.
For systemic underlying conditions such as high blood pressure or blood clotting disorders, long-term treatment and monitoring are necessary to prevent relapses. Regular blood pressure measurements, blood tests, and medication adjustments may be required.
Summary
Eye hemorrhages in dogs and cats can affect various structures of the eye and have different causes, ranging from traumatic injuries to systemic diseases. The clinical presentation varies depending on the type and location of the bleeding, from painless subconjunctival hemorrhages to painful orbital hemorrhages with exophthalmos.
Diagnosis requires a thorough ophthalmological examination and, if necessary, further diagnostic procedures such as imaging and laboratory tests. Treatment depends on the cause and severity of the bleeding and can range from simple first aid measures to complex surgical interventions.
The prognosis depends on various factors, including the affected structures, the extent of the bleeding, and the speed of treatment. Careful follow-up care is crucial for long-term treatment success and may include regular check-ups and long-term medication.
Pet owners play an important role in the early detection of eye hemorrhages and follow-up care. They should be aware of signs of eye problems and seek veterinary help immediately if they suspect an eye hemorrhage. Preventive measures such as controlling risk factors and regular veterinary check-ups can help reduce the risk of eye hemorrhages.
Outlook on current research
Research in the field of veterinary ophthalmology is continuously advancing, leading to improved diagnostic and treatment options for eye hemorrhages in pets.
New imaging techniques such as optical coherence tomography (OCT) allow high-resolution imaging of the retina and other eye structures, improving the diagnosis and monitoring of retinal hemorrhages. This non-invasive technique is increasingly being used in specialized veterinary facilities and allows for more precise assessment of damage and healing processes.
In the field of drug development, new active substances are being researched that can be used more specifically and with fewer side effects for eye diseases. Antifibrinolytic substances such as tranexamic acid are already successfully used in human medicine for eye hemorrhages and are increasingly being applied in veterinary medicine.
Minimally invasive surgical techniques such as vitrectomy (removal of the vitreous body) with small instruments are being further developed and can be used for severe vitreous hemorrhages to remove blood and restore vision. These techniques require specialized training and equipment but are becoming increasingly available in veterinary centers.
Research into genetic factors that lead to blood clotting disorders and increased bleeding tendency could lead to more targeted prevention and treatment strategies for certain breeds in the future. Genetic tests could help identify at-risk animals early and take preventive measures.
Regenerative therapies such as the use of growth factors or stem cells are being researched to promote healing of eye injuries and reduce scarring. These approaches are still in experimental stages but could offer new treatment options in the future.
The development of improved blood pressure measuring devices and protocols for pets could improve the early detection and monitoring of high blood pressure in cats, thereby contributing to the prevention of hypertensive retinopathies.
Frequently asked questions (FAQs)
- Is a subconjunctival hemorrhage in dogs dangerous?
Subconjunctival hemorrhages are usually not dangerous and heal within 1-2 weeks without treatment. However, they should be examined by a veterinarian to rule out more serious causes. - Can a bloody eye in my cat be a sign of high blood pressure?
Yes, especially in older cats, high blood pressure is a common cause of retinal bleeding. This can cause sudden vision disturbances and requires prompt treatment to prevent permanent damage. - How can I tell if my dog’s eye bleeding is an emergency?
Signs of an emergency include severe pain, sudden vision changes, severe swelling, blood inside the eye, or simultaneous bleeding from the nose or mouth. In these cases, you should seek veterinary care immediately. - Can an eye hemorrhage in my pet heal on its own?
Superficial subconjunctival hemorrhages often heal on their own. However, bleeding inside the eye or in the eye socket usually requires veterinary treatment to avoid complications. - Which dog breeds have an increased risk of eye hemorrhages?
Brachycephalic breeds like Pugs, French Bulldogs, or Pekingese have an increased risk of injury due to their protruding eyes. Breeds with known coagulation disorders such as Dobermans or German Wirehaired Pointers may also be more susceptible. - Can medications cause eye hemorrhages in my pet?
Yes, certain medications such as blood thinners (e.g., aspirin) or non-steroidal anti-inflammatory drugs can increase the risk of bleeding. Always inform your veterinarian about all medications your pet is taking. - How can I prevent eye hemorrhages in my pet?
Preventive measures include avoiding fights and dangerous play situations, regular veterinary check-ups, controlling high blood pressure in predisposed animals, and creating a safe environment to prevent injuries. - Is surgery always necessary for eye hemorrhages?
No, many eye hemorrhages can be treated conservatively with medications. Surgical interventions are only required in severe cases, such as massive bleeding in the anterior chamber or severe injuries. - Can an eye hemorrhage lead to blindness?
The risk of blindness depends on the type and extent of the hemorrhage. While subconjunctival hemorrhages rarely lead to vision loss, untreated retinal hemorrhages or severe vitreous hemorrhages can cause permanent vision damage. - How long does it take for an eye hemorrhage to heal in cats and dogs?
The healing time varies depending on the type of hemorrhage. Subconjunctival hemorrhages typically heal within 1-2 weeks, while internal eye hemorrhages may take several weeks to months for complete resorption.
Literature
- Roat, M. I.: Subconjunctival Hemorrhage. https://www.msdmanuals.com/de-de/profi/augenkrankheiten/krankheiten-der-binde-und-lederhaut/subkonjunktivale-blutungen
- Suter, P.F., Niemand, H. G. and Arnold-Gloor, S.: Praktikum der Hundeklinik. Georg Thieme Verlag 2006.
- Burk, A. and R. Burk: Checkliste Augenheilkunde (E-Book EPUB), 6th completely revised and expanded edition 2018 632 p., 343 fig., ePub ISBN: 9783132420588
- Gould D, McLellan GJ. BSAVA Manual of Canine and Feline Ophthalmology. 3rd ed. Gloucester: British Small Animal Veterinary Association; 2019.
- Maggio F, Parry N. Feline hypertensive retinopathy. Journal of Feline Medicine and Surgery. 2020;22(8):713-722.
- Ledbetter EC, Gilger BC. Diseases and Surgery of the Canine Cornea and Sclera. In: Gelatt KN, editor. Veterinary Ophthalmology. 6th ed. Hoboken: Wiley-Blackwell; 2021. p. 1082-1164.
- Plummer CE, Regnier A, Gelatt KN. The Canine Glaucomas. In: Gelatt KN, editor. Veterinary Ophthalmology. 6th ed. Hoboken: Wiley-Blackwell; 2021. p. 1173-1236.
Examination of a cat’s eye with an ophthalmoscope