An expanding armamentarium of minimally invasive and micro-invasive glaucoma surgery (MIGS) procedures is transforming glaucoma management.
“About one-half of patients with glaucoma are using two medications,” said Steven D. Vold, MD, founder and CEO, Vold Vision, Fayetteville, AR. “We know that adding a third or fourth agent often does not provide much additional intraocular pressure (IOP)-lowering benefit. However, traditional surgery with trabeculectomy and tube shunts is accompanied by significant problems.”
Dr. Vold said it is an exciting time in glaucoma surgery with several approaches available and others on the horizon. Dr. Vold shared his perspective on glaucoma devices at the Glaucoma Symposium during the 2017 Glaucoma 360 meeting.
In the past, cyclophotocoagulation performed via a transscleral approach was reserved as a last-resort procedure for end-stage glaucoma. Today, cyclophotocoagulation using micropulse laser technology (MicroPulse P3, Iridex) is a sutureless procedure that effectively reduces IOP and medication use with greater safety, said Dr. Vold.
“We are still learning how to titrate the treatment effect with diode laser cyclophotocoagulation, but the availability of a new illuminated probe is expected to enable titration of the treatment effect with enhanced precision,” he added.
Trabecular bypass procedures
Gonioscopy-assisted transluminal trabeculotomy (GATT) is an ab interno, sutureless, conjunctival-sparing procedure developed by Ronald Fellman, MD, and Davinder Grover, MD. It can be performed under topical anesthesia through a small incision, 1.8 mm to 2.4 mm, and creates a 360º trabeculotomy.
The iStent trabecular micro-bypass stent (Glaukos) was the first FDA-approved MIGS device. Two next-generation trabecular micro-bypass stents, the iStent Inject (Glaukos) and Hydrus Microstent (Ivantis), are being investigated in U.S. IDE studies.
The idea for the iStent Inject, which received the CE Mark in 2009, comes from evidence that IOP lowering is enhanced by placement of multiple iStents. Using two stents, iStent Inject allows for two access points through the trabecular meshwork (TM), expanding potential outflow through Schlemms canal, said Dr. Vold.
“The device is easily inserted, and that can make it an attractive procedure for cataract surgeons who do not do a lot of angle surgery,” Dr. Vold added.
The Hydrus Microstent received the CE Mark in 2011. It is a nitinol device that creates an entry point through the TM and stents open several clock hours to enhance aqueous outflow through Schlemms canal.
“This procedure has worked well in our patients thus far,” Dr. Vold said. “We now have encouraging results with 5 years of follow-up.”
He added that in the future, the procedure may be modified with a YAG laser to create additional access to the collector channels thus enhancing outflow if there is need to augment the IOP-lowering effect long-term.