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iStent Inject and Microgoniotomy for Glaucoma

By: Roger M. Kaldawy, M.D.
Milford Franklin Eye Center

What is glaucoma and how is it treated?

Glaucoma is a chronic disease defined by characteristic optic nerve damage.  It is a multi-factorial disease with over 300 different anatomic variations and affects over 40,000,000 people worldwide.  Glaucoma is a slowly progressive and irreversible disease and, in most cases, causes a painless loss of eyesight.  It is, in short, “the silent sneak thief of sight”. The damage to the optic nerve is commonly caused by a fluid imbalance, or pressure, in the eye, as well as possible alterations in the blood flow to the optic nerve.  It is well established that lowering the intraocular pressure can slow the process of optic nerve damage.  The degree of pressure lowering necessary to prevent optic nerve damage is individualized for each person and each optic nerve.  The greater the optic nerve damage, the lower the intraocular pressure is needed to achieve stability and prevent further optic nerve damage and further visual field loss.

If glaucoma is left untreated you may experience vision loss and eventual blindness.  Treatment strategies for glaucoma are individualized to achieve the greatest lowering of the intraocular pressure with the least amount of risk to the individual’s eyesight and well-being.  Commonly, in the United States, topical medications are used as a first line of treatment.  In many situations, multiple medications are tried to achieve the desired pressure level.  Unfortunately, there can be difficulties with compliance, cost and side effects with many of these medications and laser therapy is commonly substituted as a first line of therapy.  

What is the iStent® trabecular micro-bypass stent? 

Minimally invasive glaucoma surgical procedures, so-called MIGS involve alterations of the drainage area that are performed inside the eye.  The iStent® trabecular micro-bypass stent is a surgical therapy for patients who have mild to moderate open angle glaucoma and have been tried possibly on topical medications or laser therapy.  It is designed to improve the aqueous outflow to better lower the intraocular pressure and reduce the need for medications.  The iStent® is the smallest medical device approved by the FDA to date.  It is placed in the eye into the drainage area, so-called Schlemm’s Canal through the trabecular meshwork. The iStent® is an elective procedure.  The iStent® is potentially beneficial in helping to reduce the number of glaucoma medications and drops needed to control this condition.

What is microgoniotomy surgery?  

Microgoniotomy surgery (using the iAccess trabecular trephine device from Glaukos) is another type of MIGS. This procedure provides control of the eye pressure at lower risk than more traditional glaucoma surgeries. It alters the eye’s drainage system to lower the eye pressure and reduce the need for medications. Microgoniotomy can be done standalone or combined with iStents during cataract surgery in a tissue sparing fashion to improve resistance to outflow in glaucoma. This tissue-sparing procedure can help lower the pressure even more compared to implanting iStent alone.  During this procedure and ophthalmologist (Eye MD/ surgeon) will make 3 trephination cuts in a part of the eye’s drainage system called the trabecular meshwork. This will allow fluid to leave the eye much easier.

Benefits (how the surgery can help)

The goal of the iStent and microgoniotomy surgery is to lower your eye pressure and help preserve vision. It will not bring back vision already lost from glaucoma. After implantation, many patients are able to better control their eye pressure with fewer medications.


As with any surgery, there are risks with the iStent and microgoniotomy procedure. The surgery may not lower the eye pressure or control the glaucoma even when it is properly performed. In addition, sometimes there can be complications that do not appear in the early post operative period but may develop days, months or years later.  Further treatment or surgery to treat those complications may be needed.  As with any intraocular surgery, there may be loss of vision, blindness, loss of the eye, as well as bleeding, infection and injury to the eye or nearby body parts.

At Milford Franklin Eye Center, we use state-of-the-art technology and lasers to diagnose and treat a variety of eye problems, including glaucoma. We offer high-definition optic coherence tomography testing (OCT) that can predict glaucoma before it even happens. We also offer laser treatment when medications alone are not enough. All our offices are equipped with OCT and state-of-the-art computerized visual field testing. We operate in a state-of-the-art surgery center close to home, here at the Cataract and Laser Surgery Center of Milford. All our surgeries are performed with an anesthesiologist in the room and an IV lane, in case of an emergency.  No office-based surgery!  We were among the first surgeons in New England to introduce this new technology and we offer stellar outcomes closer to home. With 22 years of established experience and tens of thousands of procedures performed, we are happy to offer state-of-the-art medical and surgical eye care and now the iStent inject /microgoniotomy for treatment of glaucoma closer to home than ever before.

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