February 2019

COVER FEATURE

Facing complicated glaucoma cases
Ways to boost glaucoma surgical outcomes


by Rich Daly EyeWorld Contributing Writer


Malpositioned capsular tension ring (CTR) was too close to a cyclodialysis cleft. The CTR is inserted behind the iris in the ciliary sulcus with the intent to juxtapose the ring against the ciliary body processes and push the ciliary body up against the sclera in order to close off the cleft. The position of the ring was noted with the endoscope and seen to be too posterior.

The CTR was visualized with the endoscope and pushed anteriorly over the ciliary body processes. The position of the CTR is now properly placed over the ciliary body in order to close the adjacent cyclodialysis cleft.
Source: Ronald Fellman, MD


 

Surgeons highlight adjunctive tools that can improve the results of glaucoma surgery

Surgeons are using adjunctive tools and procedures to improve their surgical treatments for glaucoma. One tool is endoscopic cyclophotocoagulation (ECP, Beaver- Visitec International, Waltham, Massachusetts), which is the only cyclodestructive procedure that allows the surgeon to directly target and visualize the ciliary body processes, thereby avoiding damage to the adjacent sclera and conjunctiva, said Ronald Fellman, MD, attending surgeon and clinician, Glaucoma Associates of Texas, Dallas.
“Some glaucoma surgeries are restricted for use due to coding requirements, stage of disease or the need for concomitant cataract surgery, making them unavailable for patients,” Dr. Fellman said. “This makes it significantly harder to care for glaucoma patients. Fortunately, this is not the case for ECP, where the stage of glaucoma may be early or advanced and restrictions based on the type of glaucoma are negligible.”
The ECP system, which is performed through an ab interno approach and is compatible with microinvasive glaucoma surgery (MIGS), has a well-established track record in patients in need of combined cataract and glaucoma surgery and is especially useful in eyes with narrow angles prone to complications from filtering surgeries such as aqueous misdirection and choroidal effusions, Dr. Fellman said.
In addition, the ECP system has a unique glaucoma surgical role when used as a primary standalone IOP lowering procedure, as an adjunct to canal-based MIGS, and as a standalone camera to diagnose hidden anterior segment tube blockage and IOL maladies. As a secondary IOP lowering procedure, ECP is available for situations where a primary outflow glaucoma procedure such as a tube or a filter has failed, Dr. Fellman said.
Steven Sarkisian Jr., MD, Oklahoma City, has used ECP in combination with other MIGS. ECP has a different mechanism of action compared to the canal or suprachoroidal procedures, including the iStent (Glaukos, San Clemente, California) and the OMNI Glaucoma Treatment System (Sight Sciences, Menlo Park, California).
Brian Francis, MD, Doheny Eye Institute, University of California, Los Angeles, uses a cataract ECP procedure before and after trabecular outflow and suprachoroidal outflow surgery and expects to use it in the future with suprachoroidal shunts.
Dr. Francis’ most common use of ECP is after a tube shunt. His research has found ECP is as effective as putting in a second tube shunt.1

Diagnostic capability of endoscopy

Surgeons also have found endoscopy helps in a variety of glaucoma cases. Dr. Francis has found endoscopy effective in the pars plana and when inserting tubes.
“I’ve used them for tube revision, and this is where we have a tube in the pars plana and we can’t tell what’s wrong with it but we can go in with the endoscope and see it has blocked the vitreous or the tube is beveled the wrong way,” Dr. Francis said. “If it’s beveled interiorly, it can even get blocked with iris tissue and the vitreous so that even if an eye is vitrectomized, with an endoscope you can see the anterior and where the vitreous is in relation to the tube in its natural state without scleral depression.”
Scleral depression can change where the tube is in the eye—posteriorly or anteriorly—and prevent an accurate understanding of what is actually blocking it, Dr. Francis said.
In the case of a cyclodialysis cleft causing hypotony, the endoscope can view the extent of the cleft inside the eye. Dr. Francis used endoscopy intraocularly to determine the length of the cleft. Smaller clefts can be treated with a laser and larger clefts can be fixed with suturing, he said.
Endoscopy also helps when placing a large capsular tension ring in the sulcus and stretching it out to push to the ciliary body against the sclera and let it heal.
Dr. Sarkisian uses the endoscope to visualize the angle better in select cases of MIGS if the cornea is too cloudy.
“It is difficult to use it routinely, as the probe moves within the eye and you don’t have a third hand to keep things still with your probe hand while the dominant hand implants a device or performs a procedure,” Dr. Sarkisian said.
Dr. Fellman has found the camera portion of the endoscope especially useful in complex glaucoma cases due to altered anterior segment anatomy, such as in trauma or secondary glaucoma cases.
“Most tubes are positioned in the anterior chamber, but occasionally, the chamber is too narrow or anatomically disrupted for the tube and the camera portion of the endoscope allows the surgeon to see ‘around corners,’” Dr. Fellman said. “This greatly facilitates accurate tube positioning in the posterior chamber or even the vitreous cavity during surgery.”
Additionally, once the tube is in position, tilting the endoscope light creates an oblique view of the tip of the tube, which accentuates the definition of clear tissue, such as vitreous, he said.
“In patients with a preexisting tube where the IOP has suddenly become uncontrolled and the tube is not well visualized at the slit lamp, the endoscope allows visualization of the tip of the tube in the operating room and may explain the reason for the raised IOP,” Dr. Fellman said.

IOL surgery

Dr. Fellman has found the camera portion of the endoscope is often useful in identifying abnormalities associated with positioning of the IOL.
“When a malpositioned haptic or subluxated IOL is suspected behind the iris but not easy to see at the slit lamp, the endoscope camera and light are useful to further delineate the anatomy surrounding the IOL,” Dr. Fellman said.
It also is useful when a part of the IOL is thought to be eroding the adjacent iris but can’t be seen during a slit lamp exam.
“Thus, the position of the IOL during any intraoperative procedure can be highlighted with the endoscope revealing a variety of maladies,” Dr. Fellman said.
In basic IOL surgery, Dr. Francis said endoscopy allows surgeons to see not only the capsular support but the zonular support.
“We’ve seen cases where the anterior capsule is completely intact and yet we have a patient referred to us with a sun setting IOL, and only with an endoscope can you see that the capsule is there but there’s a lot of zonules missing so the lens is basically slipping past the zonules and around the edge of the capsule,” Dr. Francis said.
For removal of iris-sutured IOLs where there is potential bleeding in the eye due to the lens, Dr. Francis uses the endoscope to help approach posteriorly and remove the sutures without damaging the iris or the IOL.
“The endoscope is useful when you don’t know what is going on with the IOL or you are not sure what is going on peripherally with the IOL,” Dr. Francis said.

Endoscopic vs. transscleral cyclophotocoagulation

Dr. Sarkisian said ECP is commonly performed with cataract surgery and is much less inflammatory than transscleral cyclophotocoagulation (TSCPC). He uses ECP for all stages of glaucoma, including mild to moderate glaucoma where maintaining vision is paramount.
Traditionally, TSCPC been a last resort for end stage glaucoma and for severe glaucoma due to its ability to process more efficiently.
MicroPulse laser cyclophotocoagulation (Iridex, Mountain View, California) may be less inflammatory and detrimental to vision than earlier TSCPC, Dr. Francis said. He often uses it after finding aqueous production.
Dr. Fellman said TSCPC is a safer alternative if the risk of intraocular cyclodestructive surgery outweighs the benefits.
“For example, some patients are too sick for intraocular surgery, or they may have a significant bleeding diathesis, or the risk of ocular infection is too high; these patients are candidates for transscleral cyclophotocoagulation,” Dr. Fellman said. “Transillumination of the globe directly prior to transscleral cyclophotocoagulation may help delineate the anatomy of the anterior segment, allowing for a more accurate application of the laser energy to the area of the ciliary body processes.”

Reference

1. Francis BA, et al. Endoscopic cyclophotocoagulation (ECP) in the management of uncontrolled glaucoma with prior aqueous tube shunt. J Glaucoma. 2011;20:523–7.

Editors’ note: Drs. Fellman and Francis have financial interests with Beaver- Visitec International. Dr. Sarkisian has no financial interests related to his comments.

Contact information

Fellman
: rfellman@glaucomaassociates.com
Francis: bfrancis@doheny.org
Sarkisian: drsarkisian@okeyesurgeons.com

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