Eyeworld

48 | EYEWORLD | JUNE/JULY 2020 by Ellen Stodola Editorial Co-Director G SKILL FOCUS UCOMA T he term "gonioscopy" was coined to refer to "observation of the angle," ac- cording to Shakeel Shareef, MD, who said he thinks all ophthalmologists should be versed in its use. 1 Advances in gonioscopy occurred with the advent of the modern slit lamp microscope more than a century ago, en- abling angle examination with the patient seated upright. Why is gonioscopy essential? Though it is a low-tech instrument, Dr. Shareef said it is an essential diagnostic tool that helps determine the presence of neovascularization within the angle, such as in diabetes, or pres- ence of angle recession, microhyphema, or a cyclodialysis cleft associated with ocular trauma, or presence of peripheral anterior synechiae associated with uveitis. "In patients presenting with narrow angles necessitating laser iridotomy, it can help moni- tor the effect pre- and post-laser," he said. "In glaucoma patients who are being considered for topical medical therapy, the presence of an open angle will provide the rationale to pre- scribe outflow enhancing agents or consider- ation to perform laser trabeculoplasty. Go- nioscopy is an underutilized procedure that is 100% billable during an office visit and should constitute an essential part of every eyecare provider's skill set." Office-based gonioscopy is essential for preoperative MIGS planning. Identification of the scleral spur serves as the "surgical landmark," separating Schlemm's canal-based angle surgery anteriorly via the tra- becular meshwork from suprachoroidal-based surgery posteriorly via the ciliary body band, Dr. Shareef said. "If the angle is closed or significant synechiae are present, an alternate surgical procedure would need to be consid- ered," he explained What can gonioscopy identify? "For those who wish to familiarize themselves with this office-based procedure, I highly recommend they visit Wallace Alward's web- site gonioscopy.org," Dr. Shareef said. One of the challenges in performing gonioscopy, he added, is to determine whether the angle is open or not, especially in patients who present with minimal to no pigment or those who have excessive pigment present. With indentation gonioscopy, one can differentiate appositional angle closure from synechial closure, Dr. Shareef said. This is im- portant for deciding if a patient would benefit from laser iridotomy. Additionally, in patients with plateau iris, one can observe the "double hump" sign due to the anterior displacement of the ciliary body, he said. In the office, Richard Lehrer, MD, said gonioscopy can be used to diagnose primary and secondary glaucoma (normal anatomy; nar- row angles with and without synechial closure; assess risk of angle closure attack and need for lensectomy, iridotomy, or iridoplasty; and distinguish other anatomical features like pig- ment dispersion, pseudoexfoliation, neovascular glaucoma, or Fuchs heterochromic iridocycli- tis), to correctly identify congenital anomalies (immature angle or angles with cleavage abnor- malities), and to correctly identify traumatic and surgical abnormalities in the anterior segment (traumatic angle recession, haptic placement of ACIOLs, prior glaucoma procedures, or retained foreign bodies). In the laser suite or OR, it can be used to correctly identify target of laser trabeculoplasty, to correctly identify structures in the anteri- or segment for placement of MIGS devices, to correctly identify and complete ablative or catheterizing angle procedures, or to enhance lysis of anterior segment adhesions under direct visualization. Tips for learning gonioscopy Dr. Shareef noted that office-based gonioscopy is not a substitute for intraoperative gonioscopy. "The former utilizes slit lamp-based indirect gonioscopy with the patient sitting in an up- right position, whereas the latter utilizes direct gonioscopy with the patient lying in a supine position," he said. "In the office setting, gonio- scopic assessment of both eyes utilizes both Gonioscopy 101: Utilizations in the clinic and OR About the doctors Reay Brown, MD Atlanta Ophthalmology Associates Atlanta, Georgia Richard Lehrer, MD Director of Glaucoma Services Ohio Eye Alliance Alliance, Ohio Robert Noecker, MD Ophthalmic Consultants of Connecticut Fairfield, Connecticut Shakeel Shareef, MD Director of Glaucoma Service University Hospitals Eye Institute Case Western Reserve School of Medicine Cleveland, Ohio

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