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Sidebar: Gonioscopy in the Office
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How do you perform gonioscopy in the office? What is your favorite lens?
SHAN LIN, MD: I prefer the 4-mirror Posner- or Zeiss-style indirect gonioscopy lens (Ocular Instruments) (Figure 1). No coupling gel or tear solution is necessary. Another advantage is the ability to perform compression gonioscopy, which ironically is also its main downside when done inadvertently. The dynamic view of the angle with compression is a critical element in proper identification of angle structures. Sampaolesi’s line is often confused with trabecular meshwork, which may lead to improper grading as “open.” When no angle structures are seen prior to compression, compression allows for determination of synechial angle closure and distinction between chronic angle closure and occludable angle.
No coupling gel or tear solution is necessary with this type of lens.
Source: Ocular Instruments, Inc.
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In terms of resident education, these lenses afford the benefits described above. However, learners of gonioscopy may have a tendency toward unintended compression. In those cases, use of a Goldmann 3-mirror lens is an effective additional method to help in the proper identification of angle structures. I prefer to use a methylcellulose coupling agent to provide easier adherence and viewing.
TIN AUNG, FRCOphth, PhD: I use a 4-mirror Sussman or Goldmann lens in my practice. For residents, I recommend the MagnaView lens (Ocular Instruments) for ease of use, and the angle structures are clearly visible with high magnification. These features allow juniors to become familiar with angle anatomy and increase their confidence in performing gonioscopy. After gaining more expertise, they can then move on to a 4-mirror type lens like the Sussman or Zeiss-type lens.
JOHN R. SAMPLES, MD: For many years, I have taught gonioscopy to residents using a drop of proparacaine, goniosol and the 3-mirror Goldmann lens. While good in a teaching situation, the mess and fuss associated with this lens is probably not ideal for everyday practice. In a busy clinic, I prefer a no-fluid lens that can be put on the eye quickly. When gonioscopy is quick and easy, practitioners will do it more often.
Two of my favorite lenses are the MaxField AC 4M (Ocular Instruments) (Figure 2), a high-index, non-silvered, no-fluid lens. The advantage of this lens is no silver to wear off. The Volk 6-mirror lens (Figure 3) can give a quick view of the entire angle. I believe both of these lenses offer a better view overall than some of their competitors.
The Ocular Instruments MaxField AC 4 M has 4 mirrors and is not silvered.
Source: John R. Samples, MD
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The Volk 6-mirror lens has an adjustable handle that can attach to the lens at two different angles for a quick view of the entire angle.
Source: John R. Samples, MD
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