Iris Cysts


PetMD Editorial

Published Oct. 9, 2012

Iridociliary Cysts in Cats

Iridociliary cysts are also sometimes known as iris cysts, ciliary body cysts or uveal cysts. In most cases, they are benign and no treatment is necessary. However, occasionally they may be large enough to interfere with vision or with the function of the eye.


Symptoms and Types

Iridiociliary cysts may be attached to various parts of the interior of the eye. They may be lightly or darkly pigmented and are semitransparent. They may be spherical to ovoid in shape. They can vary considerably in size and there may be more than one. They may be seen in one or both eyes.

In most cases, these cysts are an incidental finding. Only when they are large enough to impair vision or interfere with the normal functioning of the eye are they problematic. Glaucoma can be a complication associated with iridociliary cysts.


Cysts may be congenital or acquired.

  • Congenital cysts are caused by a developmental abnormality in the eye and affected cats are born with the cysts.
  • Acquired cysts may be the result of trauma to the eye or of uveitis (inflammation of the dark layers of the eye.) In many cases, the cause is never known.

There is a breed predilection in Siamese cats for iridociliary cysts.


Iridociliary cysts are diagnosed with an ocular examination.


In most cases, no treatment is necessary. If uveitis or glaucoma is present, these diseases will need to be treated appropriately. Laser coagulation can be used to remove particularly large cysts if necessary.

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