Kingsdale Quick Takes
• High blood pressure can suddenly detach the retina and cause blindness in cats.
• Vision loss often signals hidden kidney or thyroid disease.
• I start amlodipine or telmisartan immediately to lower the blood pressure and address the underlying cause or illness.
• Treat within days; 60% regain sight, target systolic blood pressure under 160 mmHg.
• See your vet immediately for dilated pupils, stumbling, or bloody eyes.
Did your cat suddenly bump into furniture or stare with wide, unreactive pupils? Those scary moments often send owners searching, worried about blindness in their cat. One silent culprit is feline hypertensive retinopathy, eye damage caused by high blood pressure that most cats hide until sight slips away. When systemic blood pressure rises beyond normal limits, fragile small blood vessels in the retina can leak or tear, leading to retinal detachment and retinal hemorrhages. In this article, I will lay out the red flags, quick blood pressure tests, and treatment that can save sight in your cat.
What is hypertensive retinopathy in cats?
Feline hypertensive retinopathy is eye damage that forms when a cat’s systemic blood pressure stays high for an extended period. Persistently high blood pressure (also called systemic hypertension) forces blood through the delicate small blood vessels at the back of the eye. The vessels stretch, leak, or burst, creating visible retinal changes such as swelling, pale patches, or pinpoint retinal hemorrhages.
In severe cases, the retina can peel away, causing a sudden retinal detachment and rapid loss of vision.
We typically see hypertensive retinopathy develop when a cat's systolic blood pressure stays above 170–180 mmHg, and diastolic pressures rise above 110 mmHg.
Cats rarely show warning signs like headaches, so eye problems are often the first clue that hypertension in cats exists. Most cases trace back to an underlying condition such as chronic kidney disease, hyperthyroidism, or less commonly, cardiac disease.
By the time owners notice decreased vision, many cats already have damage in other organs, including the kidneys and brain. Regular blood pressure checks in at-risk or elderly cats help catch trouble early and protect sight.
Why high blood pressure stays hidden in cats
Many cats live with rising systemic blood pressure for months before anyone spots trouble. Early clinical signs are mild and come and go, so owners do not see a clear pattern.
Inside the body, the small blood vessels of the eyes, brain, and kidneys absorb the extra force. A slight stumble, a new heart murmur, or subtle ocular changes often get chalked up to aging.
The real underlying cause is often feline hypertension linked to chronic kidney disease, hyperthyroidism, or cardiac disease.
We vets can miss it too. Systolic blood pressure is not checked at every visit, and anxious cats may show white coat hypertension that masks the true numbers. Without calm, repeat readings, hypertension in cats often stays invisible until damage shows in the eyes, brain, or other organs.
I try to incorporate regular blood pressure checks in all my senior feline patients. Specifically, cats with kidney disease need regular blood pressure monitoring because unchecked rises in blood pressure are often the first clue to feline hypertension. Elevated systolic blood pressure can accelerate chronic kidney disease, damage the retina, and worsen overall clinical signs long before you see obvious illness in your cat.
Common underlying diseases that cause feline hypertensive retinopathy in cats
When a cat develops hypertensive retinopathy, there's usually another health issue quietly fueling the rise in blood pressure. The most common underlying problems I see include:
- Chronic kidney disease (also called chronic renal failure): As kidney function declines, it triggers an increase in systemic blood pressure that often damages the eyes.
- Hyperthyroidism: This overactive thyroid condition boosts metabolism, causing persistent hypertension and straining the delicate eye vessels.
- Less commonly, diseases affecting the brain or adrenal glands, or tumors of the kidney or liver, diabetes, and protein-losing nephropathy may also cause elevations in systemic hypertension.
However, not all cases have a clear cause. In fact, about 13–20% of hypertensive cats have what's called idiopathic or spontaneous hypertension, meaning their high blood pressure occurs without an identifiable underlying disease.
What symptoms may you notice if your cat has hypertensive retinopathy?
Not every cat will show obvious eye changes right away. Early retinal changes are subtle and often only detected during a detailed ophthalmic examination by your vet.
However, if your cat experiences sudden retinal detachment, you might notice rapid vision loss, dilated or fixed pupils (mydriasis), or unusual hesitation when navigating around your home. Sometimes, cats develop bleeding inside the eye (hyphema), making the eye appear cloudy or reddish.
In severe cases, complications like uveitis, which includes redness, squinting, or cloudy eyes, or glaucoma can occur. Chronic glaucoma may even lead to noticeable swelling of the eyeball (buphthalmos).
Of course, if you notice any changes in your cat's behavior or vision, please make sure to see your vet for advice.
How is this condition diagnosed?
When I'm concerned your cat might have hypertensive retinopathy, my first step is a thorough physical exam. Often, owners bring their cat in after noticing reduced vision, changes in pupil size (mydriasis), or redness inside the eye (hyphema).
During the exam, I'll carefully assess your cat’s overall physical condition, since high blood pressure typically affects multiple parts of the body. I'll listen closely to her heart for irregular rhythms, murmurs, or a rapid heartbeat (tachycardia). Neurological issues like dizziness, difficulty walking (ataxia), seizures, or unusual behavior can also indicate that elevated blood pressure is causing damage elsewhere.
After the physical, we'll measure your cat’s blood pressure, repeating the measurement a few times to confirm accuracy and rule out temporary stress-related spikes (white coat hypertension). A detailed ophthalmic examination follows, looking specifically at the retina to confirm signs like bleeding (retinal hemorrhages) or retinal detachment.
Because elevated blood pressure usually points to another underlying condition, I’ll likely recommend additional tests. These might include blood work to check kidney, thyroid, and liver parameters, as well as a urine test to help assess kidney function.
Identifying the real cause behind the elevated blood pressure helps us create the most effective treatment plan to protect your cat’s vision.
In many cases, referral to a veterinary ophthalmologist is recommended for a more specialized evaluation. These experts can perform advanced diagnostic tests and provide targeted care to better assess the severity of retinal damage and guide treatment decisions.
Treatment options for feline hypertensive retinopathy
My main goal in treating your cat’s hypertensive retinopathy is to quickly bring the blood pressure back down into a safe range. Lowering systolic blood pressure promptly stops the progression of damage to her retina, and it can even help the retina reattach (retinal reattachment) if caught early enough. The longer her blood pressure stays elevated, the greater the risk of permanent vision loss.
I aim for a blood pressure reading below 160 mmHg, and ideally below 140 mmHg, to protect your cat’s eyes and other organs. To achieve this, I'll usually start with medication specifically designed to lower systemic hypertension:
- Amlodipine (a calcium channel blocker) is my most common first-choice medication. Most cats start at about 0.625 mg per day, but those with very high initial pressures might require up to 1.25 mg daily. It's safe, effective, and often my preferred starting point.
- Telmisartan (an angiotensin receptor blocker) is another excellent first-line choice, especially helpful for cats with chronic kidney disease. I typically adjust the dose depending on your cat’s response and needs.
- ACE inhibitors like benazepril or enalapril might be added if we need extra control. These are often used together with amlodipine, especially in cats with underlying kidney problems, but require careful monitoring because they can affect kidney function.
- Beta blockers, like atenolol, are sometimes used if your cat has hypertension linked specifically to hyperthyroidism, but we tend to prefer other treatments first, as beta blockers can complicate breathing issues in cats with asthma.
If your cat has developed eye complications like bleeding (hyphema) or inflammation (uveitis), supportive eye care is very important. I usually recommend topical steroids to ease inflammation. If there's increased pressure inside the eye (glaucoma), I’ll prescribe special eye drops to reduce this pressure. I'll avoid certain medications (like prostaglandin analogues) because they can make inflammation worse.
What's next after starting treatment?
After starting your cat on antihypertensive therapy, I typically recheck the blood pressure within 7 days. It's important we do this promptly, because sometimes medications can lower pressure a bit too much, leading to weakness or rapid heartbeat (tachycardia). If I find her blood pressure dropping too low, I'll adjust her dosage right away to keep her comfortable.
About a week or two after starting medication, I'll also repeat a thorough ocular examination to ensure the retina is stabilizing and no further retinal hemorrhages or detachments have occurred. Regular eye checks continue periodically throughout her life, especially after making changes to her medications, to confirm her hypertensive retinopathy remains well controlled.
Since some medications (like ACE inhibitors) can impact your cat's kidney function, I'll regularly monitor her kidney health with follow-up lab tests. Depending on the original underlying cause we identified, such as chronic kidney disease or hyperthyroidism, we may also perform additional testing periodically to ensure her overall health stays on track.
What is the overall prognosis?
When we talk about prognosis, it depends largely on how severe the ocular changes are, how long they've been present, and how quickly we get the blood pressure under control.
Smaller retinal hemorrhages often heal well, leaving behind minimal scarring. Larger areas of bleeding can also heal, but they tend to cause noticeable scarring or permanent retinal damage.
If your cat has a partial retinal detachment, her chance of regaining vision is fairly good, especially if we catch and treat it early. Complete retinal detachments have a less certain prognosis. In cases where there's heavy bleeding or detachment lasting several days, the prognosis becomes less hopeful.
Studies suggest that about 60% of cats that initially lose vision due to hypertensive retinopathy will regain some sight after treatment. Cats treated consistently for more than six months have an even higher likelihood of improved vision. Interestingly, male cats tend to regain sight more frequently than females.
Overall, if we promptly manage the hypertension and stick to her antihypertensive therapy, your cat has a fair to good chance of maintaining long-term vision.
I know that all this information can feel overwhelming, but most cats do well once we catch and treat their high blood pressure. Keep an eye on behavior shifts such as bumping into walls, staring pupils, or cloudy eyes, and book a visit if you notice anything off. Routine blood pressure checks, especially for cats with kidney disease or hyperthyroidism, let us find systemic hypertension before it harms the eyes or other organs. If your cat is already on antihypertensive treatment, stick to the plan and come in for the scheduled rechecks, as recommended by your veterinarian.