Minimally Invasive Glaucoma Surgery (MIGS)
What are MIGS?
Minimally invasive glaucoma surgeries have been developed in recent years to be performed commonly during cataract surgery to decrease the intra-ocular pressure. These procedures use microscopic-sized devices and very small incisions. This reduces many of the complications that can occur as a result of standard glaucoma surgeries.
Standard glaucoma surgeries, such as trabeculectomy and ExPRESS shunts, external tube-shunts like the Ahmed and Baerveldt implants — are major surgeries. While they are very often effective at lowering eye pressure and very useful in advanced or rapidly progressing glaucoma to prevent worsening of the disease, they have a long list of potential complications.
MIGS devices have been approved by the FDA and are covered by most insurances when performed in conjunction with a cataract surgery. While they can be performed as a stand alone procedure, they are not covered by insurances when implanted this way.
Am I a candidate for MIGS?
If you have been diagnosed with mild to moderate open angle glaucoma and are on a topical glaucoma medication and you have a visually significant cataract, you are very likely candidate for a MIGS at the time of your cataract surgery. However, there are many factors that are considered when selecting a patient as a good candidate for this procedure, so you will require an exam by an eye doctor trained to properly evaluate your eye health and specific glaucoma status.
What does the MIGS procedure involve?
Either before or after the cataract has been removed from the eye during a cataract operation an additional step is necessary to perform the MIGS procedure. Depending on the device used, either one or two implants will be placed within the trabecular meshwork. The trabecular meshwork is the drainage location of the eye. It is located in a 360-degree circle in the front of the eye where the cornea meets the sclera and iris. This additional step adds about 3-5 minutes to the procedure and adds minimal additional risk.
What are the risks of MIGS procedures?
When additional steps are involved in any procedure that require additional time during surgery, it is always possible to encounter some issues such as trauma to intra-ocular structures such as the iris or cornea. These issues are extremely rare and usually self-limited. There is also the possibility that the device cannot be inserted at the time of surgery due to anatomical anomalies or implant failure. Again, this is uncommon. A more common complication is bleeding that may occur from the trabecular meshwork after the device is implanted. This can result in a hyphema, which is when blood is present within the anterior chamber of the eye. In severe cases, this can blur vision and take some time to resolve, but rarely leads to any long-term negative outcomes. Finally, there is the possibility that the device will fail to significantly lower the intra-ocular pressure. This is expected to happen at times, since these devices are known to be effective in lowering pressure around 60-80% of the time.
What are the benefits of proceeding with a MIGS procedure during my cataract operation?
Ultimately, many patients who have a MIGS procedure will achieve lowering their intra-ocular pressure which can stop or delay the progression of glaucoma. Some patients will be able to stop taking some or all of their topical glaucoma medications. While not all patients will achieve lowering of the intra-ocular pressure, the MIGS procedure is relatively very safe and doesn’t prevent a patient from proceeding with any future glaucoma interventions, such as laser procedures or standard glaucoma surgeries in the event that they are necessary in the future.