Cat Health Tip: Widely Dilated Pupils

There have been some enquiries on this site concerning dilated pupils in cats. It is something that any cat owner can readily notice. The pupils can be wide open for a good reason, namely that the room is dark. Wide open pupils allow more light to impinge upon the retina.

Dilated cat pupils
Dilated cat pupils (this is a photoshopped image by me to illustrate the page. Original photo by Ged Carroll
Two useful tags. Click either to see the articles: Toxic to cats | Dangers to cats

However, if a cat’s pupils are wide open all the time despite variations in light levels and this has happened suddenly the cause may well be high blood pressure which has damaged the blood vessels of the retina causing a loss of sight which in turn causes the iris to fail to respond the the level of ambient light which leaves the pupils fixed and wide open.

High blood pressure or hypertension is common in older cats. The cat will also appear confused and disorientated. The retina may become detached. Permanent blindness will occur unless the retina re-attaches within a few days.

There is usually a specific cause for hypertension in cats such as hyperthyroidism or chronic kidney disease (the same as in humans). In humans it can be caused by being overweight, alcohol and high salt content in the diet.

As in humans drugs to lower blood pressure are administered. In humans, statins reduce blood pressure but the drug is used to control cholesterol levels.

Please search using the search box at the top of the site. You are bound to find what you are looking for.

3 thoughts on “Cat Health Tip: Widely Dilated Pupils”

  1. It is something that any cat owner can readily notice. The pupils can be wide open for a good reason, namely that the room is dark. Where such information?

    Reply
    • Agreed — if the room is dark the pupils will be wide open but if the pupils are wide open in bright light and they are always wide open something is wrong and this should be readily noticeable. Agreed? Thanks for commenting.

      Reply
  2. Great article Michael!!

    I would also like to add that this symptom can also be caused by blindness in a cat. We had a kitty many, many years ago who had this condition. It turned out that she had Retinal Atrophy that was a result of her being permitted to eat dog food that was on the floor- While she was fed a decent diet- she wasn’t receiving enough taurine apparently. It was very sad for us but she acted as if she could see – that is unless we had to move furniture around – and she didn’t know where she was.

    Reply

Leave a Comment

follow it link and logo