You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Animals that have eyelids blink for a purpose, but sometimes they blink too much or too little,  and these are signs that something is wrong

Some creatures - such as snakes - do not have eyelids, but most domesticated animals do have eyelids. When closed they cover the eye, and their role during blinking is to :

• Protect the eye from injury
• Protect the eye from bright light
• Remove foreign material that may land on the surface of the eye
• To spread tears across the surface of the eye to keep the exposed surface lubricated and protected
• To remove tears and environmental debris to the corner of the eye where they can be drained away

Small glands in the eyelids (called Meibomian glands) produce a secretion that lubricates the lid edges . Under normal circumstances the eyelids blink several times a minute. 

Blinking increases in frequency if :

• The surface of the eye is irritated by air movement, or fine particles in the air (eg smoke, dust)
• Something is irritating the surface of the eye, such as foreign material (grass awns, dust, a loose eyelash)
• There is damage to the surface of the eye, such as a scratch or ulcer
• There is infection or inflammation present - called conjunctivitis
• The animals eyelids are positioned abnormally and are rubbing on the eye eg entropion - when the eyelids roll inwards.
• Abnormal positioning of eyelashes causing them to rub on the surface of the eye (called trichiasis)
• Irritation of the surface of the eye due to an extra row of eyelashes (called distichiasis)
• If the animal has photophobia (pain when direct light enters the eye) ...this is seen in some diseases, and usually the animal will choose to hide in dark places, and will turn away from bright light sources

If the cause of irritation is severe the animals eyelids may go into spasm so that it can hardly open its eyes. In some cases animals will scratch at or rub their eyes causing considerable self-trauma.

The frequency of blinking may be reduced or stop altogether if :

• The eyelid muscles are in spasm
• The eyelids are injured - due to swelling, a haematoma or a tumour
• The eyelid muscles are paralysed or weakened - Muscular dystrophy, Myasthenia gravis or Horners syndrome.
• There is excessive drying of the surface of the eye

In all cases of abnormal eyelid movement there is the potential for serious secondary damage to be caused to the surface of the eye.

Provet advice to owners

If you notice an increase or a decrease in the frequency of blinking have your animal examined by your vet to determine the underlying cause and have it treated as soon as possible.

Updated October 2013