Hyphema is the presence of blood within the front (anterior) chamber of the eye and is a symptom of either a serious ophthalmic disease or systemic disease. The amount of blood within the front chamber can vary. Mild hyphema may appear only as a pinkish-red discoloration to the fluid in the front of the eye, or as red blood settled out on the bottom of the chamber. Severe hyphema is when the entire chamber is filled with blood and the animal is rendered blind.
Hyphema usually originates from bleeding of the iris blood vessels, but the blood may also originate from the ciliary body (tissue behind the iris), choroidal blood vessels (tissue layer beneath the retina), or retinal blood vessels.
Causes Some causes of hyphema include:
Direct blunt or penetrating trauma to the head or eye
Severe uveitis (inflammation of the iris, ciliary body and choroid)
Blood clotting disorders
Systemic hypertension (elevated arterial blood pressure)
Retinal detachment or tearing
Chronic glaucoma
Tumors (cancer) within the eye
In some animals the cause is never determined.
Traumatic causes are more common in young cats, while hypertension, tumors and glaucoma are more common in older cats.
What to Watch For
Redness within the eye located between the cornea (the clear front covering of the eye) and the iris/pupil. The blood may hide a portion of the iris or pupil. It may settle in to the bottom of the anterior chamber due to gravity, or it may form an actual blood clot in the chamber.
Other signs of trauma (bruising, wounds), inflammation or irritation (redness, discharge) to the eye
Possibly pain with squinting or holding the eye closed
Decreased vision or blindness in the affected eye(s)
Diagnosis
Diagnostic tests may include one or more of the following:
Complete medical history and physical examination
Complete ophthalmic examination. This should include pupillary light reflex testing, Schirmer tear tests, staining of the cornea with fluorescein, tonometry (measurement of pressure within the eye), and examination of the front and back chambers of the eye under magnification
Complete blood count (CBC), including a platelet count
Serum biochemistry tests to look for involvement of other organs
Possibly a urinalysis
Specialized blood tests to evaluate the blood's ability to clot
Blood pressure testing
Specialized serum tests to evaluate the function of the thyroid gland, etc.
Possible X-rays if there are signs of other organ involvement
Treatment
Treatment of the eye is often initiated while a diagnostic work-up is underway and may include:
Topical corticosteroids, in the form of eye drops or ointments, are used to reduce inflammation within the anterior chamber.
Topical topical atropine (1%), in the form of eye drops or ointments, is used to dilate the pupil. Dilation of the pupil helps to relieve pain and to minimize adhesions between the iris and the lens.
Oral non-steroidal anti-inflammatory medications, such as aspirin, are not initially used in most cats with hyphema because these drugs may interfere with platelet function and increase the risk of further bleeding.
Treatment for glaucoma is indicated in eyes with elevated intraocular pressure. See the Client education article on glaucoma.
Home Care
Keep your cat indoors and as quiet as possible to encourage the bleeding to stop, the hyphema to settle out in the eye, and to reduce the risk of further bleeding. Restrictions in activity may be needed for up to 7 to 10 days.
Because vision is impaired in some cases, do not allow your cat to go outdoors unattended or unsupervised until the hyphema has resolved.
Do not administer human over-the-counter medications, such as Visine® or other ophthalmic products designed to reduce eye redness or irritation, because these products are ineffective for hyphema.
Do not delay in bringing your pet to your veterinarian, because some causes of hyphema are not only vision threatening, but may also be life-threatening.
