Moderate severity

Hyphema (Blood in the Eye)

Bleeding into the front chamber of the eye, seen as a red or blood-tinged pool in front of the iris — always a sign that something serious needs investigating.

⚠️ Common symptoms

A red or reddish-brown pool visible at the front of the eyeCloudiness or a change in eye colourSquinting, rubbing or holding the eye shutApparent loss of vision on the affected sideA generally unwell or off-colour cat

Hyphema is the medical term for blood pooling in the anterior chamber — the fluid-filled space at the front of the eye, between the clear cornea and the coloured iris. It can range from a faint reddish tinge to a chamber that is almost completely filled with blood, and it is never normal.

In cats, the single most important cause to rule out is high blood pressure. Feline hypertension is usually secondary to another illness, most often chronic kidney disease or hyperthyroidism, and it puts great strain on the tiny, fragile vessels inside the eye. When they give way, blood can leak into the anterior chamber or behind the retina, sometimes detaching it and causing sudden blindness. This is why a cat that turns up with a bloody eye should always have its blood pressure and kidneys checked, not just its eye examined.

Other causes include a blow to the head or eye, inflammation inside the eye (uveitis), disorders that stop the blood clotting properly, and tumours. Whatever the trigger, the eye is usually uncomfortable, and cats may squint, rub, or simply seem withdrawn.

Because hyphema so often signals a serious underlying problem — and because the eye itself can be permanently damaged by raised pressure or a detached retina — it should always be treated as urgent. With prompt care to find and treat the cause, control eye pressure and protect the eye while the blood reabsorbs, many cats do well.

🔍 Causes

In cats, one of the most common causes is systemic hypertension (often secondary to kidney disease or an overactive thyroid), which makes the delicate blood vessels inside the eye leak or burst. Other causes include head or eye trauma, inflammation inside the eye (uveitis), clotting disorders, retinal detachment and tumours. It can affect one or both eyes.

🛡 Prevention

Because hyphema is so often linked to high blood pressure in older cats, regular veterinary check-ups with blood-pressure and kidney monitoring in senior cats are the best safeguard. Keeping cats indoors or supervised reduces the risk of the traumatic causes, and prompt treatment of any eye inflammation helps prevent bleeding.

💊 Treatment

Hyphema is a sign rather than a disease, so treatment is aimed at both the eye and the underlying cause. The vet will measure eye pressure, examine the retina where possible and look for a reason — high blood pressure, a clotting problem, trauma, inflammation or a tumour. Anti-inflammatory eye drops, medication to control eye pressure and treatment of the underlying disease (for example blood-pressure control) are typical. Rest and an Elizabethan collar to prevent rubbing help the blood reabsorb, which can take days to weeks.

When to see a vet: Treat any blood in the eye as an emergency and see a vet the same day. Sudden bleeding can accompany a spike in blood pressure or a retinal detachment that threatens permanent blindness, and early treatment gives the best chance of saving both the eye and the vision.

⚕️ Medical disclaimer

  • This information is educational only and is not a substitute for veterinary advice.
  • Symptoms overlap between conditions — only a vet can diagnose accurately.
  • Never withhold treatment or self-medicate based on information found online.
  • When in doubt, call your vet. Early intervention almost always leads to better outcomes.

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