Cats' eyes are normally dilated in low light to allow more light in for better vision. However, if a cat's eyes are always dilated, it could be due to several reasons including excitement, fear, pain, side effects of medication, exposure to toxins, or underlying health conditions like high blood pressure, kidney disease, neurological disorders, or eye diseases such as glaucoma or progressive retinal atrophy. Constant dilation that doesn’t respond to changes in light may require veterinary attention as it could indicate a serious medical issue. Some cats also have naturally larger pupils due to genetics or breed traits. In summary, common causes for always dilated cat pupils include:
- Low light or dim environment
- Excitement or fear (fight-or-flight response)
- Pain or injury
- Medication side effects or toxins
- Neurological issues
- High blood pressure or other systemic diseases
- Eye conditions affecting vision or pupil response
If the dilation is persistent, accompanied by other symptoms or behavioral changes, it is advisable to seek veterinary care to rule out medical problems.