Minimally Invasive Glaucoma Surgery Has Been Adopted Rapidly in the U.S.
Key findings
- Using a nationally representative database, ophthalmologists at Mass Eye and Ear/Massachusetts General Hospital conducted a retrospective study of 160,420 patients (203,332 eyes) to examine recent trends and patterns in glaucoma surgery in the U.S.
- The number of minimally invasive glaucoma surgery (MIGS) procedures more than quadrupled between 2013 and 2018—increasing from 7,568 to 39,677—while the number of standard procedures declined from 16,215 to 13,701
- Notable demographic differences were found, with white patients significantly more likely to undergo iStent or Xen gel stent placement and younger and Black patients more likely to undergo standard surgery or goniotomy
- MIGS devices are FDA-approved only in conjunction with cataract surgery, yet 11% of iStent and 11% of CyPass were coded as standalone surgeries
- Declining reimbursements for standard cataract and glaucoma surgery combined with FDA approval of MIGS procedures that are reimbursed by insurers has resulted in the shift away from standard glaucoma surgery, which is likely to continue. The increase in MIGS adoption may also result in future restrictions in Medicare reimbursement, as has recently occurred for iStent
The various techniques of minimally invasive glaucoma surgery (MIGS) were developed as an alternative to traditional incisional glaucoma surgery, which carry a small but real risk of vision-threatening complications. The role of MIGS in glaucoma treatment is relatively unstandardized, and little information is available about overall patterns of use.
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Nazlee Zebardast, MD, MSc; Joan W. Miller, MD; and Alice Lorch, MD, MPH, of the Department of Ophthalmology at Mass Eye and Ear, and colleagues recently studied trends and patterns in MIGS use in the U.S. In Ophthalmology Glaucoma they report a more than four-fold increase in MIGS procedures over six years and a concomitant decrease in standard glaucoma surgery.
Study Methods
Mass Eye and Ear was one of four academic groups selected nationwide and awarded unique access to the American Academy of Ophthalmology's Intelligent Research in Sight (IRIS®) Registry—the nation's first electronic health record-based comprehensive eye disease and condition registry. Using this database, the researchers reviewed records of patients who underwent the following procedures from January 1, 2013, to December 31, 2018.
- MIGS—iStent placement; goniotomy or ab interno trabeculotomy; dilation of Schlemm's canal; CyPass microstent placement; Xen gel stent placement; endocyclophotocoagulation
- Traditional surgery—Trabeculectomy or placement of a glaucoma drainage device (GDD)
The analysis included 203,332 eyes of 160,420 unique patients (232,537 unique procedures).
Trends
The number of MIGS procedures increased from 7,568 in 2013 to 39,677 in 2018 while the number of standard procedures declined from 16,215 to 13,701.
In 2016, iStent placement surpassed standard surgery as the most common procedure performed each year (P<0.001). By 2017 it accounted for 44% of all glaucoma surgeries.
Frequency of Individual Procedures
- 34%—iStent placement
- 24%—Trabeculectomy
- 20%—GDD placement
- 11%—Endocyclophotocoagulation
- 11%—Other MIGS procedure
Effect of Patient and Disease Characteristics
- White patients were significantly more likely to undergo iStent or Xen gel stent placement than any other procedure
- Younger and Black patients were significantly more likely to undergo standard glaucoma surgery or goniotomy
- Eyes with severe glaucoma were significantly more likely to undergo endocyclophotocoagulation or iStent placement
Concurrent Cataract Surgery
61% of all eyes underwent concurrent phacoemulsification and glaucoma surgery. Some MIGS devices are FDA-approved for use only in conjunction with phacoemulsification, yet 11% of iStent and 11% of CyPass were coded as standalone surgeries.
Combination Glaucoma Surgery
7,638 eyes (36%) underwent more than one glaucoma procedure on the same day. The most common combination of MIGS procedures was endocyclophotocoagulation and iStent placement (55% of procedures). Goniotomy was most likely to be performed with canaloplasty (14%) or endocyclophotocoagulation (10%).
Looking Ahead
Medicare has recently restricted reimbursement for traditional cataract and glaucoma surgery. As more MIGS procedures are approved by the FDA and reimbursed by insurers, the shift away from standard surgery is likely to continue. This may be particularly true for procedures that are easily combined with cataract surgery, such as iStent insertion. Additionally, the tremendous national adoption of MIGS procedures may lead to future restrictions and changes in reimbursement.
Trabeculectomy and GDDs will retain a role in managing a niche of patients with advanced, rapidly progressive glaucoma who need marked reduction in intraocular pressure, whereas milder forms of glaucoma will be managed with MIGS. Importantly, it remains unclear whether MIGS is more effective or cost-effective than medical therapy or standard glaucoma surgery, and its long-term safety is unknown.
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