Glaucoma has been nicknamed “the sneak thief of sight” because the term refers to a group of eye diseases that gradually steal sight without warning.

In the early stages of the glaucoma, there may be no symptoms evident. Experts estimate that half of the people currently affected by glaucoma may not know they have it. Untreated glaucoma does lead to permanent damage of the optic nerve and the result is a visual field loss. This vision loss can manifest into blindness.

The optic nerve is responsible for carrying images from the eye to the brain. It serves its purpose acting like an electric cable with over a million wires. Vision loss is caused by damage to the optic nerve in some way.


Distinct symptoms of glaucoma being or not being present do not affect the fact that an almost inevitable complication of the disease is vision loss. Glaucoma typically affects peripheral vision first; but can also affect central vision. Early vision loss is so subtle that it is commonly not noticed by the patient. Moderate to severe vision loss is more readily noticed by the patient, especially with careful examination of the full visual field. Left untreated, the disease will cause the visual field to become increasingly narrow, affecting central vision and finally progressing into blindness.


Risk Factors and Diagnosis

  • Elevated eye pressure
  • People with a family history of glaucoma
  • Diabetics and Afro-Americans are three times more likely to develop primary open angle glaucoma
  • Asians are prone to develop angle-closure glaucoma

High pressure within the eye, also known as intraocular pressure (IOP), was once thought to be the main cause of optic nerve damage leading to glaucoma. Although it is abundantly clear that IOP is a risk factor, we are now aware that other factors must also be involved because even people with “normal” levels of pressure can experience vision loss from glaucoma.

Although raised intraocular pressure is a definite and important risk factor for developing glaucoma, a certain threshold for intraocular pressure that causes glaucoma does not exist. Nerve damage may develop at a relatively low pressure in one individual, while another person may have high eye pressures for years and never develop nerve damage. This is one of the reasons that it is so significant to eye health to see an ophthalmologist regularly.


While there is no cure for glaucoma yet, medication or surgery can slow or prevent further vision loss. Appropriate treatment depends upon many factors including the type of glaucoma. Early detection is absolutely vital to stopping the progress of the disease.

Although intraocular pressure is only one of the risk factors for developing glaucoma, it is a major one. Lowering it via pharmaceuticals or surgery is currently the stronghold of glaucoma treatment. Laser treatments and topical medications are both being pursued in research with the hopes of one day contributing to controlling intraocular pressure and preserving visual field.


iStent® Trabecular Micro-Bypass: add an exciting glaucoma technology to your cataract surgery.

istent-eye.jpgTechnology has always played an important role in eye care. Today, almost every aspect of vision is connected to a product or procedure that wasn’t available even ten short years ago. The cataract surgery you are scheduled for is a good example of how innovations can make a difference. Every aspect of it utilizes recently developed technology that will help us improve your vision. Today, this includes managing your mild-to-moderate open-angle glaucoma: because now we are able to add another step to your cataract surgery that allows you to treat your open-angle glaucoma in a completely new way. This is important because once diagnosed, you and most patients like you will spend the rest of your lives putting one, two or even three different kinds of drops in every day. Unfortunately, all of these drops will not only be inconvenient, but potentially very expensive. The iStent Trabecular Micro-Bypass Stents designed to reduce your eye pressure and you can have it done at the same time you have cataract surgery.

iStent: the world’s smallest medical implant delivers big results in mild-to- moderate open angle glaucoma.

iStent-small.jpgWhile mild-to-moderate open-angle glaucoma is very common, many people are unaware of their condition, especially in the early stages, when their vision may be unaffected. In many people, open-angle glaucoma is characterized by an increase in the intraocular pressure (IOP) of your eye. This pressure is caused by the buildup of fluid within the eye. Too much fluid raises pressure, which can cause the gradual loss of vision. And while glaucoma moves slowly, its damage is irreparable.
The world’s tiniest medical device—iStent—is 20,000 times smaller than the intraocular lenses (IOL) used in your cataract surgery. But the size of iStent is only part of its story. By increasing the eye’s ability to drain fluid, this technology is designed to reduce the pressure in your eye.
In a U.S. clinical study, 68% of glaucoma patients who received iStent remained medication free at 12 months while sustaining a target IOP of ≤ 21 mmHg vs. only 50% of patients who underwent cataract surgery alone.

iStent-parts.jpgiStent works like the stents used to prevent heart attacks and strokes. When blood vessels get clogged, a stent creates access to the vessel flow. While a highly innovative technology, how iStent works is elegantly simple:

  • If you have glaucoma, over time the eye’s natural drainage system becomes clogged
  • iStent creates a permanent opening through the blockage to improve the eye’s natural outflow
  • Restoring this mechanism lowers and controls pressure within the eye

iStent: managing glaucoma while treating your cataracts.

iStent® is implanted during your cataract surgery procedure. Once implanted, iStent will begin working to safely and effectively manage pressure. What’s more, patients who receive iStent may experience a reduction in glaucoma medications; but this will be at the discretion of your physician.

Indication For Use.

The iStent® Trabecular Micro-Bypass Stent (Models GTS100R and GTS100L) is indicated for use in conjunction with cataract surgery for the reduction of intraocular pressure (IOP) in adult patients with mild to moderate open-angle glaucoma currently treated with ocular hypotensive medication.


The iStent® is contraindicated in eyes with primary or secondary angle closure glaucoma, including neovascular glaucoma, as well as in patients with retrobulbar tumor, thyroid eye disease, Sturge-Weber Syndrome or any other type of condition that may cause elevated episcleral venous pressure.


Gonioscopy should be performed prior to surgery to exclude PAS, rubeosis, and other angle abnormalities or conditions that would prohibit adequate visualization of the angle that could lead to improper placement of the stent and pose a hazard. The iStent® is MR-Conditional meaning that the device is safe for use in a specified MR environment under specified conditions, please see label for details.


The surgeon should monitor the patient postoperatively for proper maintenance of intraocular pressure. The safety and effectiveness of the iStent® has not been established as an alternative to the primary treatment of glaucoma with medications, in children, in eyes with significant prior trauma, chronic inflammation, or an abnormal anterior segment, in pseudophakic patients with glaucoma, in patients with pseudoexfoliative glaucoma, pigmentary, and
uveitic glaucoma, in patients with unmedicated IOP less than 22 mmHg or greater than 36 mmHg after “washout” of medications, or in patients with prior glaucoma surgery of any type including argon laser trabeculoplasty, for implantation of more than a single stent, after complications during cataract surgery, and when implantation has been without concomitant cataract surgery with IOL implantation for visually significant cataract.

Adverse Events.

The most common post-operative adverse events reported in the randomized pivotal trial included early post-operative corneal edema (8%), BCVA loss of ≥ 1 line at or after the 3
month visit (7%), posterior capsular opacification (6%), stent obstruction (4%) early postoperative anterior chamber cells (3%), and early post-operative corneal abrasion (3%). Please refer to directions for use for additional adverse event information.

Caution: Federal law restricts this device to sale by, or on the order of, a physician. Please reference the directions for use labeling for a complete list of contraindications, warnings, precautions and adverse events.


Trabectome is a relatively new and incredible micro incisional surgical treatment for glaucoma. There are very few doctors locally and nationally that have the expertise and technology to perform the surgery.

Dr. Singh is one of those select doctors having the specialized training, skill, experience, and technology to make this distinguished treatment available in the Houston area. Please click here to learn more about Trabectome.