‘Draining the sink’ to treat glaucoma with minimally invasive surgery

by Mark L. Gonzalez, MD, Clinical Director, MedStar Eye Institute
May 17, 2018

Today’s surgeons can use minimally invasive techniques for many conditions that require surgery. For example, knee replacements can be performed with smaller incisions than in years past, and some skull-base tumors can be removed through the nostrils.

Glaucoma patients now have the opportunity to undergo minimally invasive surgery for their disease. Minimally invasive glaucoma surgeries, or MIGS, offer faster recovery, less pain and fewer complications than traditional surgery.

In order to understand how these procedures work, it’s important to understand what glaucoma is and how it affects the eyes. I tell my patients that surgical treatment for glaucoma is similar to draining a kitchen sink with a faucet that never shuts off. If the drain backs up, the sink overflows. The goal is to keep the excess fluid moving steadily out of the eyes.

LISTEN to me describe minimally invasive glaucoma surgery in this Medical Intel segment on WTOP Radio.

What is glaucoma?

Glaucoma is an excess of fluid in the eye. When we’re talking about “fluid in the eye,” we’re talking about the fluid in the actual eyeball. This is something people get confused about all the time. Glaucoma has nothing to do with tear production on the surface of the eye or the feeling of having excessive wetness on the surface of the eyes.

The ciliary body, an internal part of the eye, makes fluid. Another internal part of the eye, the trabecular meshwork, drains the fluid back into the venous system. The trabecular meshwork is similar to a small sponge. Eye fluid doesn’t simply run through the spongy tissue. Rather, it seeps through the meshwork steadily. People with glaucoma have more resistance in the trabecular meshwork, which causes the fluid to drain through much less efficiently. When the fluid doesn’t drain properly, excess pressure builds up in the eyes and can cause vision problems or vision loss over time.

There is not yet a cure for glaucoma. We have two options to manage the disease: decreasing the amount of fluid that is produced or improving the drainage system. MIGS can address both sides of this equation.

People with mild to moderate glaucoma may be candidates for MIGS procedures. Patients who already have advanced glaucoma usually require traditional surgery. Though minimally invasive surgeries pose less risk to patients, most glaucoma doctors would agree they don’t reduce eye pressure as well as trabeculectomy, the traditional and more complex glaucoma surgery.

How minimally invasive glaucoma surgery reduces risk to patients

The vast majority of glaucoma patients are controlled with medication and do not need surgery. However, when surgery is needed, we’ve traditionally relied on trabeculectomy as well as tube shunts to reduce intraocular pressure. Though these surgical procedures are effective, they are more complex than may be necessary for many patients.

In traditional trabeculectomy, we make an external drain where the fluid exits the interior eye underneath the conjunctiva, which is the membrane/skin that covers the front of the eye. This provides access for fluid to move from the inside of the eye to the outside, but the conjunctiva is incredibly thin and fragile. Risks involved with traditional trabeculectomy include eye infections, such as endophthalmitis, scarring, extreme low eye pressure, and failure of the surgery, which can happen right away or over time.

Though severe cases of glaucoma may ultimately require trabeculectomy, MIGS can be a safe option to treat people for whom medication is no longer enough but whose glaucoma isn’t severe enough for traditional surgery.

MIGS are procedures done internal to the eye aimed at reducing intraocular pressure via extremely small incisions. These may involve implantation of a device, removal of the trabecular tissue or laser application. All of these techniques serve to bridge the gap between medication therapy and the need for trabeculectomy. These surgeries are exciting to ophthalmologists like me because they give us a lower-risk option to treat patients. We can perform some of these surgeries from inside of the eye, reducing the risk of infection and the duration of recovery.

Types of MIGS procedures

We often perform a MIGS at the same time as a patient’s cataract surgery We are able to perform these procedures through the same small incisions used for cataract surgery (2.4mm), thus reducing the trauma to the eye.

We currently have three ways to perform MIGS:

  • Eye stent, in which we place a tube in the eye to help fluid drain directly out of the eye and bypass the trabecular meshwork.
  • Kahook blade, in which we remove a portion of the trabecular meshwork to increase the efficiency of fluid drainage.
  • Endocyclophotocoagulation (ECP), in which we go behind the iris (the colored portion of the eye) to destroy some of the cells that produce eye fluid.

If your doctor recommends glaucoma surgery, ask about the risks and benefits of the procedure, as well as whether minimally invasive surgery is an option for you. Though risks such as infection or inflammation are possible, these risks are far lower with MIGS than with traditional glaucoma surgery.

There’s always a risk that you may need another procedure down the road or that you may eventually require trabeculectomy if your condition worsens. But for many patients, minimally invasive glaucoma surgeries allow us to delay larger, riskier procedures until they’re absolutely necessary.

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at the MedStar Eye Institute.

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Category: Healthy Living, Medical Intel     Tags: glaucomaglaucoma surgeryglaucoma treatmentminimally invasive glaucoma surgery