What is Glaucoma?
Glaucoma is a multifactorial disease of the eye. The eye pressure is higher than what the eye can tolerate and the optic nerve in the back of the eye is damaged. This damage leads to a slow loss of side vision and later the central vision. Because the loss of side vision is slow, people do not realize they are losing their vision. Glaucoma has the nickname “the thief in the night” as people are unaware of their vision loss until they have lost a significant amount of their vision.
Treatment of Glaucoma
Lowering the eye pressure to safe level is the goal in treating glaucoma. This is usually done by topical medications and laser treatment (S LT) initially. If the eye pressure is still not controlled, there are a variety of surgical procedures for lowering the eye pressure which are;
- Shunt procedures
- ExPress Mini Shunt
Fluid Flow Inside the Eye
The ciliary body located behind the iris (brown or blue portion of the eye) produces a fluid called the aqueous humor. This fluid flows in front of the lens and through the pupil into the anterior chamber. The anterior chamber is the space in front of the eye between the iris and cornea (clear portion of the eye surrounded by the white portion of the eye called the sclera). The fluid exits the eye through the trabecular meshwork located in the angle where the cornea, sclera, and iris meet inside the eye. The meshwork is like cheese cloth through which the fluid flows into Schlemm’s canal and into a collector channel. The collector canal empties into a vein. There is a constant flow of fluid into the eye and flow out of the eye. When the flow has difficulty flowing through Schlemm’s canal, the eye pressure elevates resulting in glaucoma. The primary cause of elevated intraocular pressure in open angle glaucoma comprising 75% of resistance to outflow is blockage located in the juxtacanalicular tissue.
New Glaucoma Procedure Called iStent
The iStent is indicated for the treatment of mild to moderate glaucoma to be performed during cataract surgery. After the cataract has been removed and the intraocular lens has been inserted, the iStent is inserted into the trabecular meshwork.
The iStent is the smallest medical device known tobe implanted in the human body. The dimensions of the iStent are designed to optimize aqueous humor flow from the eye. The iStent is inserted through the anterior portion of the trabecular meshwork into Schlemm’s canal. The design provides access to the collectorchannels. The retention arches maintain placement of the iStent.
Snorkel 0.25mm x 120um bore diameter
The iStent is composed of surgical-grade nonferromagnetic titanium preloaded in a sterile inserter.
FDA Study Results
Patients were put into two categories of either having cataract surgery only and those that had an iStent placed during cataract surgery.
iStent and Cataract Surgery Group– 68% of patients had eye pressures under 21 no medication
Cataract Surgery Only– 50% of patients had eye pressures under 21 no medications
This difference was statistically significant.
iStent and Cataract Surgery Group– 64% of patients had a greater than 20% reduction in eye pressure
Cataract Surgery Only– 47% of patients had a greater than 20% reduction in eye pressure
The iStent is new procedure that is used during cataract surgery to lower eye pressures in mild to moderate glaucoma patients. The risks are minor and it is a new valuable tool in treating glaucoma.