At roughly a third of a millimeter in length and diameter, the iStent inject® is among the world’s smallest implantable medical devices to help people with mild-to-moderate open-angle glaucoma. Here, ophthalmologist Tarek Youssef, M.D. explains how the micro-invasive procedure works, and how it can help preserve your vision.*

About iStent inject 

High intraocular pressure, or pressure from fluid buildup inside the eye, is both a cause and symptom of glaucoma. To help lower that pressure, Glaukos Corporation created the iStent inject®, a tiny medical device implanted in the eye using minimally-invasive surgery. Made of titanium, the snorkel-like device lowers pressure by creating a tiny channel to drain excess fluid. The treatment can potentially reduce your need for additional glaucoma surgery or medication.

How iStent is implanted 

The iStent procedures are often, though not always, performed during cataract surgery, and usually at a surgical center or hospital. The procedure involves the following steps: 

• Before surgery, an eye drop is applied to the eye to numb it. 
• A small hole is created in the front of your eye.
• The iStent injector is inserted between your iris and cornea.
• Guided by a special lens, the device is placed into your eye fluid drainage network.
• A second iStent may be injected at a different spot.

With the iStent(s) in place to bypass blockages in the eye’s drainage system (trabecular meshwork), natural fluid outflow can be restored.

What to expect

Normal intraocular pressure ranges between 10 and 21 mmHg (millimeters of mercury). Youssef says the iStent, like other MIGS procedures, typically reduces pressure to the mid-teens. Immediately after surgery:

• Your eye may feel sore and irritated, as though there’s an eyelash under your lid,
• Using medicated eye drops may cause a burning sensation, and
• Your eyes might tear or get watery more than usual. 

These are common symptoms, and usually disappear after a couple of days. 

While the advantage of the iStent procedure is its higher safety margin, Youssef says it’s not always as effective at lowering eye pressure as a trabeculectomy, in which a new drainage pathway is surgically created. Ask your ophthalmologist about what treatments might be best for you, and why.

*Tarek Youssef. (2016, July 2). iStent inject Animation MIGS [Video file]. Retrieved from https://www.youtube.com/watch?v=4liVsI5lExA

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