Hyphema consists of the accumulation of blood in the anterior chamber of the eyeball, that is, in the space between the cornea and the iris. It can be caused by causes circumscribed to the eye itself or by systemic causes, which will determine whether it is a unilateral hyphema (affecting only one eye) or bilateral (affecting both eyes). Determining the specific cause that originates the hyphema will be essential to establish an adequate treatment and establish a prognosis about the process.
If you are interested in learning more about hyphema in dogs, its symptoms and treatment, don't miss this article on our site at in which we talked about its aetiology, its diagnosis and its treatment.
What is hyphema in dogs?
The anterior chamber of the eyeball is the space between the cornea and the surface of the iris. The aqueous humor is housed in the anterior chamber, which should be transparent under normal conditions. However, sometimes there is a extravasation of blood from the anterior uvea (iris and ciliary body) into the anterior chamberIn this situation, the components of the blood (cells and blood plasma) mix with the aqueous humor, causing it to take on a reddish color.
The accumulation of blood in the anterior chamber of the eyeball is called hyphema or hyphema. Usually, it is usually observed in the lower part of the eye, since the blood content falls due to the effect of gravity. However, when the dog moves its head, the blood is distributed throughout the anterior chamber, showing a homogeneous reddish color. It should be noted that the blood in the anterior chamber does not usually clot easily due to the release of fibrinolysins (enzymes that dissolve fibrin clots) by the iris. For this reason, the clots usually do not appear until 4-7 days after the start of the bleeding.
Depending on the severity and extent, ocular hyphema can be classified as:
- Grade I: when it occupies less than a third of the anterior chamber.
- Grade II: when it occupies half of the anterior chamber.
- Grade III: when it occupies three quarters of the anterior chamber.
- Grade IV: when it occupies the entire anterior chamber.
Causes of hyphema in dogs
When we talk about the causes of hyphema in dogs, we may be talking about local causes (in the eye itself) or systemic causes. Next, we are going to see them in more detail.
Local causes of hyphema in dogs
There are various eye disorders that can trigger a hyphema in dogs:
- Eye trauma: this is the most frequent cause.
- Uveitis: inflammatory process that affects the uvea (the vascular tunic of the eye)
- Glaucoma.
- Retinal detachment.
- Ocular neoplasms: such as lymphomas.
- Congenital eye anomalies.
Generally, causes circumscribed to the eye give rise to unilateral hyphemas, that is, they affect only one eye.
Systemic causes of hyphema in dogs
The two systemic causes that can cause a hyphema in dogs are:
- Arterial hypertension.
- Coagulation disorders: thrombocytopenia, coagulopathies such as Von Willebrand disease, anticoagulant poisoning, ehrlichiosis, etc.
When the cause is systemic, hyphema is usually bilateral, that is, it affects both eyeballs.
Symptoms of hyphema in dogs
The clinical signs associated with hyphema in dogs are as follows:
- Reddish band in the anterior chamber of the eye: it will be more or less extensive depending on the severity of the process. When the animal moves its head, the blood is dispersed throughout the chamber, showing a homogeneous reddish color.
- Blepharospasm: eye closure due to ocular pain
- Epiphora: continuous tearing.
Diagnosis of hyphema in dogs
The diagnosis of hyphema in dogs must be carried out by a veterinarian specialized in ophthalmology. Specifically, the diagnosis of hyphema in dogs includes:
- Complete ophthalmological examination: The anterior chamber of the eye should be studied from a lateral perspective using a slit light in order to correctly locate the hemorrhagic focus. In case of unilateral hyphema, it is important to carry out a complete examination of the he althy eye, since it can provide useful information for diagnosis.
- Tonometry: to measure intraocular pressure.
- Ocular ultrasound: it is a very useful diagnostic tool that also helps to establish a prognosis about the process.
- Blood analysis and blood pressure measurement: it is essential in case of bilateral hyphema, since the cause is usually systemic.
To reach a definitive diagnosis of ocular hyphema, it is necessary to rule out the following differential diagnoses:
- Hemorrhagic inflammatory exudate in the anterior chamber: Unlike hyphema, the hemorrhagic inflammatory exudate has a more yellowish color, a more dense and occupies the entire anterior chamber (not just the lower part).
- Vitreous haemorrhage: in this case the reddish coloration is behind the pupil (in the vitreous chamber). However, the possibility of concomitant hyphema and vitreous hemorrhage should not be ruled out. In case of vitreous hemorrhage, examination of the fundus will be difficult or impossible.
- Hemorrhage in the cornea or iris: Observing the anterior chamber from a lateral perspective, it will be possible to differentiate the precise location of the hemorrhagic focus.
Treatment of hyphema in dogs
Hyphema is considered an ophthalmological emergency that requires immediate medical attention Therefore, when you suspect that your dog may be suffering from an intraocular hemorrhage Do not hesitate to go to a veterinary clinic as soon as possible. The most usual thing is that the veterinary team that treats you proceeds to stabilize the ophthalmological emergency in situ, and then refer the case to an ophthalmology specialist.
Treatment for hyphema in dogs should include:
- Topical or systemic anti-inflammatories: corticosteroids are generally used, since NSAIDs (Non-Steroidal Anti-Inflammatory Drugs) are not recommended due to their possible platelet antiaggregant.
- Mydriatics or cycloplegics: These are drugs that cause pupil dilation and are used in cases of hyphema to prevent the appearance of synechiae (adhesions). Tropicamide can be used in mild hyphemas (grade I or II) or Phenylephrine 10% in severe hyphemas (grade III and IV). However, it must be taken into account that the use of these drugs is controversial, since they can predispose to an increase in intraocular pressure.
- Topical carbonic anhydrase inhibitors: such as dorzolamide or brinzolamide. They will only be used in cases of ocular hypertension.
- Analgesics: Opioids such as buprenorphine can be used when there is eye pain, especially in traumatic cases. We also suggest this post about natural pain relievers for dogs.
- Animal rest.
When the hemorrhage is organized in the form of a clot, it is advisable to perform an intracameral injection of TPA (Tissue Plasminogen Activator). Occasionally, surgical removal of the clot may be necessary. These procedures should only be performed by specialist ophthalmic surgeons.
Prognosis and complications of hyphema in dogs
The prognosis of hyphema in dogs depends on the originating cause and its extension:
- Grade I: usually clear up in less than a week.
- Grades II and III: take several weeks to resolve.
- Grade IV: Often cause atrophy of the eyeball, also known as phthisis bulbi.
Usually, the blood lodged in the anterior chamber gradually drains through the iridocorneal angle. However, sometimes intraocular hemorrhage can lead to the following complications:
- Formation of intraocular synechiae: Adhesions may form between the clot and the cornea or between the clot and the iris.
- Ocular hypertension (values above 25 mmHg) and glaucoma.
- Waterfalls.
- Retinal detachment
- Retinal degeneration
- Atrophy of the eyeball or phthisis bulbi.
- Blindness.
