ProvidersPedro Cervantes, MD * Adrian J. Elfersy, MD * Robert A. Flores, MD * Wei Huang, MD, PhD * Veena Rao, MD * Robert M. Saltzmann, MD, FACS * Boyd K. Vaziri, MD
* = Fellowship Trained
What is glaucoma?
Glaucoma is a disease of the optic nerve, which transmits the images you see from the eye to the brain. The optic nerve is made up of many nerve fibers (like an electric cable with its numerous wires). Glaucoma damages nerve fibers, which can cause blind spots and vision loss. Glaucoma is often, but not always, caused by a buildup of the pressure inside the eye, known as intraocular pressure (IOP). When the aqueous humor (a clear liquid that normally flows in and out of the eye) cannot drain properly, pressure builds up in the eye. The resulting increase in IOP can damage the optic nerve and lead to vision loss.
The most common form of glaucoma is primary open-angle glaucoma, in which the aqueous fluid is blocked from flowing back out of the eye at a normal rate through a tiny drainage system. It is known as open-angle because the anterior chamber angle, which is the portion of the drainage system visible by examination, appears open. In other words, the outflow blockage cannot be directly seen with typical examination techniques. Most people who develop primary open-angle glaucoma notice no symptoms until their vision is impaired.
Glaucoma causes include elevated eye pressure (intraocular pressure or IOP) due to the eye’s inability to drain fluid efficiently. If the drainage angle is blocked, excess fluid cannot flow out of the eye, causing the fluid pressure to increase. Congenital glaucoma is a rare type of glaucoma that develops in infants and young children. It can be hereditary, and it happens when the eye’s drainage system doesn’t develop fully or correctly before birth.
Glaucoma can often be caused by another eye condition or disease. This is known as secondary glaucoma. Someone who has a tumor or people undergoing long-term steroid therapy may develop secondary glaucoma. Other causes of secondary glaucoma include: eye injury, inflammation of the eye, abnormal blood vessel formation from diabetes or retinal blood vessel blockages, use of steroid-containing medications (pills, eyedrops, sprays) or pigment dispersion.
Risk Factors for glaucoma
- African or Hispanic heritage
- Corneas are thin in the center
- Family members with glaucoma
- Farsightedness or nearsightedness
- Diabetes, migraines, high blood pressure, poor blood circulation or other health problems affecting the whole body
- Over age 40
People with more than one of these risk factors have an even higher risk of glaucoma and should talk with an ophthalmologist. Early detection and treatment can protect your vision.
The goal of glaucoma treatment is to lower your eye pressure to prevent or slow further vision loss. Your ophthalmologist will recommend treatment if the risk of vision loss is high. Treatment often consists of eyedrops but can include laser treatment or surgery to create a new drain (and bypass the damaged one) in the eye. Glaucoma is a chronic disease that can be controlled but not cured. Ongoing monitoring (every three to six months) is needed to watch for changes. Several different treatments are available from our glaucoma doctors in SouthPark, Belmont, Concord, Huntersville, Matthews, Salisbury, Statesville, and University. You should ask your eye doctor if you have any questions about glaucoma or your care.
WHEN IS A TUBE SHUNT PROCEDURE necessary?
Glaucoma drainage implant surgery, sometimes referred to as a tube shunt, may be needed in patients with glaucoma that is not controlled by medications and/or laser treatment. It may be needed either as primary glaucoma surgery in certain types of glaucoma or after failure of trabeculectomy surgery.
In trabeculectomy surgery, a tiny drainage hole is made in the sclera (the white part of the eye). This opening allows fluid to drain out of the eye under the delicate membrane covering the eyeball known as the conjunctiva. The fluid does not spill out of the eye but is simply re-routed to another area of the eye where it is absorbed by the internal blood vessels. Locally-applied medications or injections may be used to help keep the hole open.
With tube shunt surgery, most of the device is positioned on the outside of the eye under the conjunctiva (eye tissue), usually underneath the upper eyelid. The tube portion of the device is carefully inserted into the front chamber of the eye, typically just in front of the iris (colored part of the eye). The fluid drains through the tube, into the area around the back end of the reservoir of the shunt. The fluid collects here and is reabsorbed. One cannot feel the implant and it is usually not visible unless one lifts the eyelid or opens the eye very widely.
The iStent is a device implanted in the tissue near the base of the cornea (trabecular meshwork) that improves your eye’s natural fluid outflow and safely lowers eye pressure. It is implanted during cataract surgery, and spares important eye tissue that is often damaged by traditional surgery.
It is the smallest medical device ever approved by the FDA, and is so small it can’t be seen or felt after the procedure is over.
Most studies found statistically significant reductions in mean intraocular pressure and the use of ocular medication when iStents are implanted. The iStent has also been found to be very safe, with a safety profile similar to that of cataract surgery.
The iStent can also decrease the risk of large eye-pressure fluctuations associated with patients who don’t adhere to their medication regimens. It is also a great option for patients who have preservative allergies.
XEN Gel Stent
The XEN gel stent is a minimally-invasive glaucoma surgery (MIGS) that makes significant reductions in intraocular pressure while decreasing the need for other medications. It was engineered to provide the same long-term pressure-lowering benefits as traditional first-line glaucoma filtration surgeries (namely trabeculectomy and Express shunt procedures) with much less surgical trauma to the eye and less risk of sight-threatening complications that are often associated with large pressure fluctuations after glaucoma surgery.
MIGS approaches are revolutionizing the overall treatment of glaucoma. Less surgical trauma to the eye means safer interventions that may be done at earlier stages of the disease and allowing for faster recovery than after traditional glaucoma surgery. In fact, most MIGS procedures are designed to be performed on patients with mild to moderate glaucoma in the hopes of controlling this relentless disease and minimizing the burden of eye drops and other medications earlier in its course. However, the XEN gel stent is one of the few FDA-approved MIGS options that can also be placed in patients with more advanced glaucoma, providing patients with even the most severe stages of glaucoma many of the same safety and recovery benefits afforded to those with less severe disease.
The XEN gel stent is also one of the few currently-available MIGS treatments that can be performed as a standalone procedure, rather than having to be done at the same time as cataract surgery. Therefore, patients with glaucoma who have already had cataract surgery may be ineligible for most MIGS options. The XEN gel stent affords suitable patients in this situation the opportunity to benefit from many of the advantages of MIGS.
eyeSmart® Eye health information from the American Academy of Ophthalmology. The Eye M.D. Association.