The Impact of Age
One may wonder why the risk for glaucoma increases with age. One explanation is that with increasing age, we lose trabecular cells, which have a role in keeping the trabecular meshwork functioning well. One may also ask the opposite question: why are some babies born with congenital glaucoma? In this case, there may be abnormal development of the trabecular meshwork, such that it does not function properly. Clearly, the trabecular meshwork plays a very important role, and some even call glaucoma a “trabecular meshwork disease.”
Treatments for the Eye's Drainage System
Medications
How do glaucoma treatments affect the trabecular meshwork? The currently available medications either decrease aqueous humor production (“turning down the faucet”) or increase aqueous humor outflow via a pathway that does not directly involve the trabecular meshwork. However, new drugs that were approved in late 2017 (Vyzulta™ and Rhopressa®) directly target the trabecular meshwork, which is very exciting, since these are the first new glaucoma drugs in over two decades. In addition, these drugs directly target the diseased trabecular meshwork! The year 2018 will be very exciting as we see how these new medications actually work in everyday patients.
Lasers
Laser trabeculoplasty (selective laser trabeculoplasty, SLT, as one example) targets the trabecular meshwork. Once these cells are activated, they release molecules that help improve outflow via the trabecular meshwork and its associated structures, thereby lowering eye pressure.
New Surgical Techniques
Finally, this is also an exciting time in the development of new surgeries for glaucoma, as some of these new surgeries target the trabecular meshwork and its associated structures.
Some of these surgeries are termed “minimally invasive or micro invasive glaucoma surgeries” (MIGS), and some are being paired with cataract surgery to lower eye pressure and/or decrease the number of medications patients need to use in early to moderate-stage glaucoma.
One such surgery using the Trabectome device targets the trabecular meshwork and removes it, opening access to Schlemm’s canal as a way to lower eye pressure.
Another surgery uses the iStent, a very tiny titanium stent that makes an opening into the trabecular meshwork, thereby bypassing it and allowing fluid to flow into Schlemm’s canal and lower eye pressure.
The CyPass® micro-stent, which is combined with cataract surgery to lower eye pressure by bypassing the trabecular meshwork altogether was voluntarily removed from the market In 2018 by the manufacturer. Learn why the manufacturer took this step, and what you should do if you have already had the CyPass micro-stent procedure.
Finally, Xen is a very small gel stent that can be performed as a standalone procedure by itself, and is less invasive than standard trabeculectomy surgery. However, its effectiveness has not yet been measured directly against trabeculectomy.
While these surgeries are not suitable for everyone, and often do not achieve the very low eye pressures that some patients require, it is a promising time in the development of new treatments targeting or bypassing the trabecular meshwork, and therefore glaucoma.