Gonioscopy necessary before initiating glaucoma therapy, specialist says

LAS VEGAS — Gonioscopy is an essential tool for making an accurate diagnosis and understanding the biological mechanisms at work in glaucoma suspects, according to a specialist speaking here at the OSN Las Vegas meeting.

Alan L. Robin, MD, spoke on the importance of gonioscopy for diagnosing glaucoma.

"Gonioscopy is the most important factor in making a correct diagnosis," said Alan L. Robin, MD, an OSN Glaucoma Section Member.

According to Dr. Robin, less than half — or 45.9% — of respondents to a practice patterns survey conducted by the American Academy of Ophthalmology said they perform gonioscopy at the initial patient consultation.

As for which device to use, Dr. Robin said: "I don' t care as long as you use it."

He said the Goldmann goniolens and the Zeiss four-mirror goniolens — which are indirect goniolenses — are both excellent. The Zeiss four-mirror device has a small-diameter lens and is ideal for narrow angle indentation, although it is not optimal for visualization of the corneal wedge sign.

Dr. Robin laid out a few tips for properly performing gonioscopy. These include starting with visualization of the interior angle, which is the deepest and most pigmented, having the patient look "over the hill" toward the mirror to obtain a better view of the angle, looking for the corneal wedge and performing indentation gonioscopy.

"By pushing, you can tell the difference between something that is closed and is totally zippered shut and something that has the opportunity to be opened," Dr. Robin said. "It gives you an idea of the pathology beneath."

Other gonioscopy tips include examining the other eye for recession or angle-closure disease and using topical glycerin to assist in visualization of factors such as debris, angle closure and peripheral anterior synechia.

Dr. Robin concluded that "gonioscopy is very important, and hopefully by learning these simple tricks ... you will learn how to do it much more effectively."