What is MIGS?

The goal of all glaucoma surgery is to lower eye pressure to prevent or reduce damage to the optic nerve.

Standard glaucoma surgeries (such as trabeculectomy and external tube-shunts) are major procedures that bypass the conventional drainage pathway to drain fluid from inside the eye to underneath the outer membrane of the eye (conjunctiva).

While they are very often effective at lowering eye pressure and preventing progression of glaucoma, there are several potential complications. The MIGS group of operations were developed to reduce some of the complications of the standard glaucoma surgeries.

MIGS procedures were introduced about 15 years ago and they use microscopic-sized equipment and tiny incisions. While they do reduce certain complications, some degree of effectiveness is traded for the increased safety. The MIGS group of operations are divided into several categories:

Using very small tubes that are inserted into the eye and drain fluid from inside the eye to underneath the conjunctiva, two devices — Xen and PreserFlo — seem to make the trabeculectomy operation safer. They may require some additional, minor, tweaking procedures (needling) to counteract later scarring that may impede the drainage.

The trabecular meshwork can either be removed (Trabectome, GATT, Kahook blade) or by-passed by implanting a tiny device (iStent, Hydrus). Another approach is to dilate Schlemm’s canal with a jelly-like substance (canaloplasty) with or without cutting through the trabecular meshwork (OMNI, iTrack, STREAMLINE, VIA360). These procedures are most useful in early to moderate stages of glaucoma, and when performed in conjunction with cataract surgery. The Hydrus has the longest published follow-up data.

In these types of operations, the front of the eye is connected to the suprachoroidal space between the retina and the wall of the eye (sclera) to augment the drainage of fluid from the front of the eye. This operation can lower pressures enough to be useful even in moderately severe glaucoma. The Allo-Flo which uses processed human sclera to maintain the opening is the most recent addition. 

Several new approaches to glaucoma surgery show promise for better safety. Your ophthalmic surgeon should use the one he/she is most confident in for your type and stage of glaucoma. As with all new procedures, time and much follow up study are required to see which ones of these many procedures will remain useful for helping glaucoma patients in the long-term.

Article by Robert L. Stamper, MD. Last updated on July 21, 2026.