Cat Eyes – All About Your Cat’s Eyes


Cat eyes, everything you wanted to know

The senses consist of sight, hearing, smell and touch all of which combine to give your cat a window to the outside world. The eyes of the cat have evolved as that of a nocturnal predator. The eyes of the cat are large in relation to the skull and provide him with a wider field of vision than that of humans (295 degrees compared to 210). This helps the cat judge distance, which is essential for hunting prey. Cats have two features that help them see in very low light.

Tapetum lucidum (which means bright tapestry)  is a specialised layer of flat cells found beneath cat’s retina. These mirror-like cells allow light to bounce off them and back onto the retina. When a bright light is shone into a cat’s eyes, you will see the familiar glow of the light bouncing off the tapetum lucidum (see pictures below).

Elliptical pupils are able to increase to a greater size than round shaped pupils. The larger the pupil, the more light enters the eye, helping the cat to see better in low light.



Are cats colour blind?

Cats do not see colour in the same way that we do. They can see some colours and are able to distinguish between certain colours such as red and blue.

Structure of the cat eye:

The eye consists of:

  • Pupil – The black opening at the centre of the iris which controls how much light is let into the eye. In bright conditions, the pupil is a small slit (see image above), in dark conditions it is large.

  • Iris – The iris is the pigmented muscle surrounding the iris. Eye colour is the result of pigment in the iris.

  • Sclera – White of the eye.

  • Third eyelid (haw) – Also known as the nictitating membrane, the third eyelid is the white/transparent inner eyelid. It removes debris from the surface of the eye and distributes tears. You can sometimes see the third eyelid when the cat is sleepy or unwell.

  • Cornea – The whole, clear front part of the eye, which you can see when you look at your cat.

  • Lens – The lens sits behind the iris, its function is to focus and refract light onto the retina at the back of the eye.

  • Conjunctiva – The membrane which covers the front of the eyeball and the inside of the eyelids.

  • Conjunctival sacThis is the space between the eyelids and the eyeball that is lined by the conjunctiva.

  • Retina – The light-sensitive layer of tissue located at the back of the inner eye.

  • Tapetum Lucidum – A layer of flattened cells located at the rear of the eye found in nocturnal animals. The tapetum lucidum reflects light onto the cornea, increasing light for night vision.

  • Posterior chamber -The space between the lens and the retina containing a clear jelly.

  • Eyelid – The upper and lower folds of skin which cover the eye when it is closed.

  • Anterior chamber – Found between the cornea and the lens.

Eye signals and behaviour:

The eyes (along with other visual cues such as the ears and tail) can also give an insight into the mood of your cat.

Wide open (large) pupils suggest strong emotional arousal be it fear or excitement.

Small (slit-like) pupils can be indicative of neutral emotions or predatory and aggressive behaviour.

Cat eye colour:

All kittens are born with blue eyes, they change colour around 8 to 12 weeks as melanin granules accumulate in the irises.

The eyes come in a number of colours in cats, including blue, green, orange, brown and yellow. Some cats have odd coloured eyes such as one blue, one yellow
which is known as heterochromia.

odd eyed cat

odd eyed cat

Odd-eyed cat

Odd-eyed cat

golden eyed cat

golden eyed cat

Golden-eyed cat

Golden/yellow-eyed cat

Blue eyed cat

Blue eyed cat

Blue eyed cat

Blue eyed cat

Green eyed cat

Green eyed cat

Green eyed cat

Green eyed cat

Brown eyed cat

Brown eyed cat

Brown eyed cat

Brown eyed cat

The cat in the image below has sectoral heterochromia, as you can see, one of the irises is two colours.

Heterochromia in cats

Eye disorders:

There are many disorders that can affect cats, too many to list here. Common eye problems cats encounter are:

  • Cataracts (opacity of the lens)
  • Glaucoma (increase in fluid pressure in the eyeball)
  • Uveitis (inflammation of the inner structures of the eye)
  • Corneal ulcers
  • Retinal diseases
  • Retinal detachment
  • Tumours
  • Corneal disease
  • Eye infections
  • Foreign object lodged in the eye
  • Conjunctivitis (inflammation of the conjunctiva)
  • Keratoconjunctivitis sicca (KCS/dry eye)
  • Trichiasis (eye irritation from the lashes)
  • Entropion (eyelid rolled inward)
  • Eye worms

Brown spots in the eyes (melanoma, melanocytes)

The following conditions can cause blindness:

Symptoms of eye disorders:

Symptoms can vary depending on the condition, but be alert for the following:

  • Watery eyes (epiphora)
  • Cloudy eyes
  • Different sized pupils
  • Lumps and bumps on any part of the eye
  • Pawing at the eye
  • Painful eye
  • Film over the eye
  • Bulging or sunken eye (enophthalmos)
  • Squinting
  • Sudden swelling (chemosis)
  • Irritation

Blind cats:

All cats are born with their eyelids fused shut, their eyelids begin to open around the second week of life.

Aside from the above, which occurs in all newborn kittens, some cats will be born blind, others will become blind at a later stage in life either through disease or trauma. Blind cats can and do go on to live a full and happy life. More information on blindness in cats can be found here.


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