Glaucoma
April 2022
by Liz Hillman
Editorial Co-Director
While modern angle surgery has been a boon for patients and physicians wishing to avoid or delay more invasive glaucoma procedures and/or reduce the number of topical medications, cyclodialysis cleft, while rare, is still a complication.
Daniel Lee, MD, said this occurs when a device or surgical instrument physically disinserts the ciliary body from the scleral wall during surgery.
“IOP can swing exquisitely high when the cleft closes.”
Sarah Van Tassel, MD
“Cyclodialysis clefts represent the pinnacle of MIGS-related complications. Even a small cleft can act as an aqueous sink, diverting fluid away from physiologic outflow systems, almost always resulting in profound hypotony,” Dr. Lee said. “Vision is predictably going to be significantly impaired. Cleft closures are often accompanied by dramatic pressure elevations, which are unpredictable in timing and scale. These issues are compounded by heightened patient expectations as MIGS procedures are often described as the lower risk, ‘easier,’ and less vision-impacting options.”
Sarah Van Tassel, MD, told EyeWorld that a cyclodialysis cleft can occur any time during angle surgery when anatomy posterior to the trabecular meshwork is engaged with a surgical instrument or MIGS device.
“Intuitively, I would expect this most during procedures that involve horizontal or sweeping motion in the angle, but in review of the FDA MAUDE database,1 my group found that surgeries like placement of the CyPass device [Alcon, withdrawn from the market], iStent/iStent inject [Glaukos], and XEN Gel Stent [Allergan] can also cause clefts,” Dr. Van Tassel said.
Dr. Lee said with the popularization of angle-based glaucoma procedures, there is an increased incidence of cyclodialysis cleft, but glaucoma procedures are not the only intraocular surgery that can result in this complication. A paper published decades ago described six cases where patients had hypotony due to inadvertent cyclodialysis after IOL implantation.2
Risk factors
Dr. Lee said he’s seen cyclodialysis cleft arise from all angle-based surgeries, with the rate seeming proportional to the extent and duration of the angle treatment. “Perhaps the most common cause of cyclodialysis cleft is a suboptimal gonioscopic view of the angle during surgery,” Dr. Lee said. “This may be due to corneal opacities from corneal edema, arcus, prior scarring, etc. Unclear angle anatomy may be another cause. Very lightly pigmented meshwork can challenge landmark identification.”
Other risk factors for this complication include patients who are not cooperative or who have involuntary tremors, both of which should be noted prior to surgery, Dr. Lee said.
Preventative measures
Prevention, Dr. Lee said, starts at the preop office visit. He said that gonioscopy can help identify potential pitfalls, such as pale TM, prominent peripheral iris vessels, and blood in Schlemm’s canal from elevated episcleral venous pressure.
“Patient-related factors that would limit effective communication, such as language barriers, cognitive deficits, and poor cooperation, are also factors to consider when determining type of procedure and/or level of anesthesia,” he said.
With a poor view of the angle being the greatest risk factor for cyclodialysis cleft, Dr. Lee said that it goes without saying that surgeons should take particular care in maintaining a pristine view of the angle.
“Don’t go where you can’t see,” Dr. Lee said, noting that measures to increase visibility include turning the patient’s head and scope adequately to maintain an en face view of the angle.
Dr. Van Tassel also said that good visualization of the angle is paramount. She said to stop immediately if the wrong anatomy becomes engaged or if the patient experiences discomfort.
“Angle surgery should be painless,” she said.
If the trabecular meshwork is pale, Dr. Lee advised staining the target tissue with trypan blue or inducing blood into Schlemm’s canal. He said trypan blue is preferable because it is more reliable and avoids the potential for excess bleeding, which could further complicate the view and procedure.
A general pearl for surgical gonioscopy that Dr. Lee provided is to have a gentle touch with the gonioscopy prism to avoid corneal striae that could obscure the view.
“I tell residents and fellows to allow gravity to do most of the work. The fingers only guide the positioning of the lens. Using a hands-free gonioprism has come in handy for novice surgeons [in that it] allows the fellow hand to stabilize the device and minimize tremor,” he said.
Management of cyclodialysis cleft
While Dr. Lee said there are reports of patients recovering vision years after developing a cleft, there is risk for permanent damage without timely intervention. If the cleft is small (less than 1 clock hour), Dr. Lee said it’s likely to close without surgery.
Dr. Van Tassel said clefts require management when they cause symptomatic hypotony.
“If diagnosed early in the postoperative period, I tend to reduce steroid use and be fairly permissive with inflammation in order to aid in healing, and I’ll use atropine to help appose the ciliary muscle to the eye wall/scleral spur,” she said.
Dr. Lee follows a similar regimen for smaller clefts, explaining that a topical cycloplegic encourages apposition between the uveal tissue and the internal scleral wall.
If the cleft doesn’t close within 4–6 weeks, Dr. Lee said overlapping rows of argon laser along the affected area could help. His laser settings are 700–900 mW, 200 micron spot size, and 500 ms. This intervention, Dr. Lee noted, can be painful and may need to be repeated. As such, he finds surgical intervention more reliable and patient friendly.
Dr. Lee tends to identify and close larger clefts (1–3 clock hours) surgically.
“The majority of patients undergoing MIGS procedures are pseudophakic, which fortunately is a prerequisite for an ab interno approach to cleft closure. Many fascinating and creative techniques have been described,” he said, noting that the simplest technique, in his opinion, is the “bucket handle” technique, which uses a 9-0 Prolene on a double-armed long needle. “Following a conjunctival peritomy overlying the cleft, a 27-gauge needle can be passed just posterior to the iris approximately 2 mm from the limbus. The suture needle is then docked and externalized. This is repeated for the other side of the cleft. The suture is tied off and buried in the sclera or can be placed in a pre-formed partial thickness scleral groove.”
Clefts larger than 3 clock hours may require multiple sutures, Dr. Lee added. Another technique is the “sewing machine” maneuver.
“Following a conjunctival peritomy, a partial thickness scleral groove should be made approximately 2 mm from the limbus, parallel to the cleft. Prolene suture is loaded into a 27-gauge needle, and the needle is passed underneath the iris from the inside out. The loaded Prolene is pulled and externalized through the scleral groove while the needle is retracted back into the eye. The needle is then passed approximately 1 mm adjacent to the original pass and the suture and the still-loaded suture is externalized,” Dr. Lee explained. “This maneuver is repeated for the entire extent of the cleft. The result should be the free ends of the suture at each end with loops in between. The loops are cut and adjacent sutures are tied together.”
For larger clefts, Dr. Lee said cyclophotocoagulation over the affected area as an adjunct to suture closure is an option to encourage adhesion.
If the patient is phakic, Dr. Lee said an ab externo technique with a full thickness scleral flap with direct suturing of the uveal tissue to the underlying scleral surface is usually needed.
Dr. Van Tassel ended by saying that it’s important to follow cleft patients more closely in the postop period because the “IOP can swing exquisitely high when the cleft closes.”
About the physicians
Daniel Lee, MD
Director
Glaucoma Research Center
Wills Eye Hospital
Philadelphia, Pennsylvania
Sarah Van Tassel, MD
Assistant Professor of Ophthalmology
Weill Cornell Medicine
New York, New York
References
- Duong A, et al. Adverse events associated with microinvasive glaucoma surgery reported to the Food and Drug Administration. Ophthalmol Glaucoma. 2021;4:433–435.
- Meislik J, Herschler J. Hypotony due to inadvertent cyclodialysis after intraocular lens implantation. Arch Ophthalmol. 1979;97:1297–1299.
Relevant disclosures
Lee: Allergan, Glaukos, New World Medical
Van Tassel: AbbVie, New World Medical
Contact
Lee: daniellee@willseye.org
Van Tassel: sjh2006@med.cornell.edu
