Gonioscopy

To determine whether a person has open angle glaucoma or narrow angle glaucoma we examine the angle.  This is the area at the edge of the iris (the colored part of the eye) where it joins the white part of the eye (sclera).  The front of the eye (cornea) makes it impossible to view this directly.  In order to see the angle it is necessary to use a contact lens with a mirror. 

Gonioscopy is performed as part of the normal examination of people when glaucoma is a consideration.  A numbing drop is placed in the eye and the contact lens is then placed on the eye.  It is painless. 

If the iris is seen to be blocking the drainage channels then the doctor may feel that the patient has narrow angle or angle closure glaucoma and recommend appropriate treatment.

As the eye ages, angles that were open in the past may become closed or narrow.  For this reason it is important that gonioscopy be repeated periodically.