{"id":730,"date":"2026-11-04T06:54:40","date_gmt":"2026-11-04T14:54:40","guid":{"rendered":"https:\/\/www.marketplaceveterinary.com\/blog\/?p=730"},"modified":"2026-11-04T06:54:41","modified_gmt":"2026-11-04T14:54:41","slug":"why-does-my-cats-pupil-look-different-in-one-eye-understanding-unequal-pupils","status":"publish","type":"post","link":"https:\/\/www.marketplaceveterinary.com\/blog\/why-does-my-cats-pupil-look-different-in-one-eye-understanding-unequal-pupils\/","title":{"rendered":"Why Does My Cat’s Pupil Look Different in One Eye? Understanding Unequal Pupils"},"content":{"rendered":"
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Cats\u2019 pupils naturally change size throughout the day, widening in dim light and narrowing when things get bright. But if you suddenly notice that one pupil looks larger than the other, it\u2019s worth paying attention. <\/p>\n\n\n\n

Unequal pupils, known as anisocoria, can have many possible causes, including problems involving the eye or nervous system. At MarketPlace Veterinary Hospital<\/a> in El Dorado Hills, California, our team can evaluate changes in your cat\u2019s eyes, and help determine what may be behind them.<\/p>\n\n\n\n\n\n\n\n

What Is Anisocoria in Cats?<\/h2>\n\n\n\n

Anisocoria simply means that the pupils are different sizes. Normally, both of your cat\u2019s pupils should respond similarly to changes in light. With cat anisocoria, one pupil may remain noticeably larger or smaller than the other.<\/p>\n\n\n\n

It isn\u2019t always obvious which eye is abnormal. Depending on the underlying problem, the affected pupil may be the larger one or the smaller one. You might also notice that the difference becomes more pronounced in bright or dim lighting.<\/p>\n\n\n\n

Anisocoria isn\u2019t a disease itself. Instead, it\u2019s a sign that something is affecting the eye, the structures around it, or the nerves that control pupil size.<\/p>\n\n\n\n

Why Is One Cat Pupil Larger Than the Other?<\/h2>\n\n\n\n

If you notice that one of your cat’s pupils is larger than the other, there are several possible explanations. Some involve the eye itself, while others affect the nerves that control the pupil.<\/p>\n\n\n\n

Potential causes of unequal pupils can include:<\/p>\n\n\n\n