Glaucoma is a group of eye diseases associated with progressive and characteristic damage to the optic nerve that can cause permanent vision loss. It is most typically associated with increased eye pressure due to buildup of fluid inside the eye. The eyeball produces a special fluid for nourishment, and this fluid drains out of the eyeball through a drainage system located in the space where the clear part of the eye meets the colored part of the eye. This area is called the anterior chamber angle. Anything that impedes the fluid flow in this angle will cause a fluid buildup (hence pressure buildup) inside the eye.
Glaucoma is the second leading cause of blindness worldwide after cataracts. But unlike cataracts, damage caused by glaucoma is typically irreversible.
There are four major categories of glaucoma:
- Open-angle glaucomas occur when the anterior chamber angle is open but the drainage system is not functioning well, or is scarred or blocked by pigment or other substances. Primary open angle glaucoma (the most common type of glaucoma) belongs to this category. The early onset of primary open-angle glaucoma does not involve any symptoms or pain. It is often called the “silent thief of sight.” That is why early detection through state-of-the-art eye exams is so important.
- Angle closure glaucomas occur when the anterior chamber angle is closed, leading to drainage system impediment. There are two types of angle closure glaucomas: acute and chronic. The acute type is associated with high eye pressure and sudden onset of eye pain and redness, blurry vision, haloes around lights, as well as headache, nausea and vomiting. The chronic type, the second type of angle closure glaucoma, is usually painless.
- Congenital glaucoma usually presents at birth and can be associated with eye abnormalities and systemic diseases.
- Secondary glaucoma is associated with steroid use, eye infection or inflammation, eye trauma or systemic diseases.
Certain segments of the population are more prone to develop glaucoma, including those of African-American, Irish, Russian, Japanese, Chinese, Hispanic, Inuit and Scandinavian descent. Other risk factors include:
- Family history of glaucoma
- Eye trauma
- Chemical injury
- Eye infection or inflammation
- Previous eye surgeries
- Steroid medications
- Moderate to severe nearsightedness or farsightedness
Medical treatments consist of eye drops or oral pills. Eye drops and pills decrease eye pressure by either decreasing fluid production in the eye, improving fluid drainage out of the eye, or both. Eye drops are used on a regular basis. Although some patients tolerate pills well, pills may have side-effects such as nausea or tingling sensations in toes and fingers. In rare cases, pills can cause life-threatening allergic reactions. So they are mainly reserved for situations where the eye pressure must be brought down temporarily before proceeding with the other treatment options.
Laser treatments are designed to facilitate fluid drainage out of the eyeball. These are office procedures which take about 15 minutes to perform. The eye pressure is checked about 1 hour after the procedure. There are 4 types of laser procedures that are used for glaucoma treatment:
- Laser peripheral iridectomy (LPI) – Involves creating a small hole in the colored part of the eye
- Iridoplasty (IP) – In this procedure tiny burns are created around the entire periphery of the iris.
- Argon laser trabeculoplasty (ALT) – In this procedure tiny burns are made on the spongy part of the drainage system called trabecular meshwork.
- Selective laser trabeculoplasty (SLT) – A laser is used to unclog the trabecular meshwork from pigment or other substances that can impede the fluid outflow.
For complex and advanced cases of glaucoma, Dr. Hennen uses surgical treatments, including:
- Trabeculectomy with Ologen – During a trabeculectomy procedure, Dr. Hennen creates an opening in the eye drainage structure by removing a small piece of tissue. This opening allows the aqueous humor fluid to drain out of the eye, thus lowering eye pressure. The gap is then covered by the surrounding tissue and Ologen, which is a special collagen implant used during surgery to prevent/minimize post-operative scarring. Scarring can lead to failure of the surgery.
- Glaucoma shunts with Ologen – Glaucoma shunts are used as drainage devices for glaucoma patients. These devices are typically made of strong silicone or polypropylene or steel. When implanted into the eye, they divert excess fluid from the eye through a tube or a stent. The shunt is positioned on the surface of the eyeball but is covered by the surrounding tissue, Ologen and the eyelid to decrease its visibility. Dr. Hennen uses several different glaucoma drainage devices, depending on the patient’s specific eye condition:
- BAERVELDT® tube shunt
- Molteno® tube shunt
- Ahmed™ tube shunt
- Ex-PRESS® shunt
- iStent trabecular micro-bypass – For patients with cataracts and glaucoma, the iStent trabecular micro-bypass is a procedure used to improve the natural outflow of eye fluid by creating a permanent opening in the trabecular meshwork. This spongy tissue area is part of the drainage system and is located near the cornea and iris. The iStent is a minimally-invasive glaucoma surgery device that can lower eye pressure when implanted during cataract surgery.
- Gonioscopy-assisted transluminal trabeculotomy (GATT) – This is a minimally-invasive procedure to reduce eye pressure by cutting the spongy tissue near the clear part of the eye and iris to improve fluid drainage out of the eyeball.
- Endoscopic cyclophotocoagulation – For patients with cataracts and glaucoma, endoscopic cyclophotocoagulation is a procedure that can be done during cataract surgery to lower eye pressure. The process uses a laser to target the fluid-producing cells in the eye in order to decrease the amount of fluid that is produced. Dr. Hennen uses a high-resolution camera and laser inserted through a tiny incision in the eyeball to perform this treatment.