Procedure, Lenses And Grading of Gonioscopy

Submitted on March 27, 2012

What is Gonioscopy?

A gonioscopy procedure is essentially an eye examination used to take a closer look at the front of your eye, especially the anterior chamber angle with direct observation. Although you may tend to believe that any examination of the eye is likely to be painful, gonioscopy grading is relatively painless and also helps identify if the area in the eye from where the fluid drains is open or closed. The gonioscopy is a regular eye test that is performed alongwith a number of other routine examinations and also helps identify if you are at a higher risk of developing glaucoma, depending on variables such as your age and family history of the condition.

How Is it Performed?

The test is performed using some very high end gonioscopy lenses and each one is chosen depending on the purpose of the examination. Moreover, the mechanism for each procedure also relies heavily on the type of lens selected. For example, when a koeppe direct goniolens is placed directly over the cornea of the eye, some amount of lubricating fluid is used to prevent damage to the eye. As a result of its rather steep curvature, this lens eliminates any internal reflection thereby allowing a much clearer view of the iridocorneal angle.  When the goldman indirect goniolens is used, the cone shaped device makes use of a layout of mirrors in order to reflect the light from the iridocorneal angle towards the eye specialist and is best used with the patient sitting in an upright position. The zeiss indirect goniolens is very similar to the goldman lens but uses a set of prisms instead of mirrors. The efficient arrangement of prisms allows for the visualization of the iridocorneal angle in four quadrants of the eye at the same time.


During gonioscopy grading, your ophthalmologist will use some eyedrops in order to numb the eye and you will then be asked either to lie down or sit on a chair. The chosen lens will then be placed in the front of your eye and a narrow beam of light will be directed into the eye. The entire procedure shouldn’t take anymore than about 10 minutes. The major risks of the procedure are limited to the fact that, because of the eyedrops used to numb the eye, your vision may be blurred for several hours after the test. Avoid rubbing your eyes for at least twenty minutes just after the test as you will not be able to gauge the pressure you apply on the eyeball - which could lead to significant damage.