Adhesions of the Eye’s Iris and Swelling of Eye in Cats

By PetMD Editorial on Oct. 18, 2012

Iris Bombe - Complete Posterior Synechiae in Cat

Synechiae are adhesions between the iris and other structures in the eye, either the cornea or lens. Iris bombe occurs when there is a complete adhesion between the cat’s iris and the capsule of the lens of the eye, creating a 360 degree area of adhesion. This degree of adhesion results in a billowing of the iris forward into the eye.

Symptoms and Types

Symptoms seen with iris bombe include:

  • Eye bulging
  • Eye pain
  • Red eyes
  • Squinting
  • Corneal lesions, such as ulcers
  • Excessive tearing and discharge
  • Glaucoma
  • Variation in the color of the iris
  • Opacity of the lens
  • Uveitis
  • Decreased papillary reaction to light


  • Cat fight injury
  • Chronic infection
  • Corneal ulcer
  • Foreign body injury to the eye
  • Hyphema (bleeding in the front part of the eye)
  • Penetrating wounds to the eye
  • Surgery


Diagnosis is based on an ophthalmic examination, which involves examining the structures of the eye. Tonometry may be performed to measure the intraocular pressure (the pressure within the eyeball).


In many cases, treatment may not be necessary. However, when glaucoma occurs in conjunction with iris bombe and synechiae, it must be treated. In cases like this, laser surgery may be necessary to release the adhesions from the iris.

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