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What is glaucoma?

Glaucoma is a group of diseases that affects internal drainage of the eyeball and optic nerve - a part of the eye responsible for vision. The eyeball is filled with a special fluid, called “aqueous fluid” (not to be confused with tears). This fluid naturally flows from the eyeball through a drain located inside the eyeball. This drain is called the “trabecular meshwork.” It is located in the angle formed by the cornea (the clear part of the eye) and the iris (the colored part of the eye). Under normal circumstances, there is a balance between fluid production and fluid outflow. In such circumstances, the eye pressure remains normal – ranging between 8 mmHg to 22 mmHg. When the balance is disturbed, the fluid builds up inside the eyeball, leading to increased eye pressure, characteristic optic nerve damage, and vision loss. Glaucomas are typically (but not always) associated with high eye pressure. In fact, up to 50% of patients with glaucoma have normal eye pressure during initial presentation. Although some patients are born with glaucoma or develop it in childhood, most patients who develop glaucoma, do so later in life.

What are the three major types of glaucoma?

The three major types of glaucoma include: open angle glaucomas where the angle is opened but is malfunctioning or clogged, angle closure glaucomas where the angle is narrow or closed, and mixed-mechanism glaucoma where an initially opened angle becomes closed later.


What are the risk factors for glaucoma?

  • Older age

  • African American or Hispanic descent

  • Scandinavian descent

  • Increased eye pressure

  • Diabetes 

  • Hypertension

  • Trauma

  • Long-term steroid use

  • Family history positive for glaucoma

  • Certain medications


How do you diagnose glaucoma?

While eye pressure measurement was once the standard way to screen for glaucoma, it can miss certain kinds of glaucoma like normal tension glaucoma. Dr. Hennen uses all the most advanced tools to identify all types of glaucoma.

At Eyecare MPLS, Dr. Hennen uses state-of-the-art diagnostic tools, including:

  • Fundus photography: photos of the optic nerve and retina (thin film that lines the inside of the eye)

  • Visual field testing of central and side vision

  • Spectral domain optical coherence tomography (SDOCT): high-speed laser imaging of the angle, optic nerve, and retina

  • Ultrasound biomicroscopy: detailed imaging of the iris, ciliary body and lens

  • Eye pressure measurements with Goldman applanation tonometry


How do you treat glaucoma?

There are 3 main categories of glaucoma treatment:

  • Medical treatment

  • Laser procedures

  • Glaucoma surgeries


What is the medical treatment for glaucoma?

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. Therefore, they are mainly for short-term use.

What are the laser procedures for glaucoma?

Laser treatments are designed to facilitate fluid drainage out of the eyeball. They work by creating new drainage paths for inner-eye fluid, or creating an open angle, or both. These are office procedures which take about 2 minutes to perform. The eye pressure is checked about 20 minutes after the procedure.


What are the three types of laser procedures for glaucoma?

There are 3 types of laser procedures that Eyecare MPLS offers for glaucoma treatment:

  • Selective laser trabeculoplasty or SLT: A laser is applied to the inner drain to unclog it from pigment or other substances that can impede the fluid drainage.

  • Laser peripheral iridotomy or LPI: This uses a laser to creates a small hole in the iris (the colored part of the eye) to facilitate fluid outflow, and to lift the iris away from the lens zonules (suspensions that hold the lens in place).

  • Iridoplasty: In this procedure, tiny laser burns are created around the entire periphery of the iris to make it thinner in order to facilitate the drain opening.


What are the different glaucoma surgery options?

Dr. Hennen performs two major groups of glaucoma surgeries, including: minimally invasive glaucoma surgeries (MIGS) and glaucoma filtering surgeries.

Minimally invasive glaucoma surgeries are usually performed at the end of cataract surgery and take about 2-3 minutes to complete.


Examples of minimally invasive surgeries include:

  • iStent® – The iStent is a small stent that is inserted into the spongy part of the inner drain called the “trabecular meshwork”. It lowers your intraocular pressure and can potentially reduce your need for glaucoma medication.

  • Goniotomy – In this surgery, Dr. Hennen uses a specialized viewing tool, a goniolens, to view the internal drain of the eye. She then uses a special instrument to cut out the inner drain to ferry excess fluid out of the eye. 

  • Endoscopic cyclophotocoagulation – This process uses a laser to target the fluid-producing cells in the eye 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.

For complex or advanced glaucoma cases Dr. Hennen performs filtering glaucoma surgeries designed to create a new drain for the eyeball.


Examples of filtering glaucoma surgeries include:

  • Tube shunts – Tube shunts are typically made of silicone or polypropylene materials. When implanted into the eye, they divert excess fluid from the eye through a tube. The fluid goes into a small reservoir on the surface of the eyeball. Then, your body disposes of the fluid naturally.

  • The Ex-PRESS® shunt - This is a stainless-steel shunt. In contrast to a tube shunt, it creates an additional drainage path within your eye on a smaller scale.

  • Trabeculectomy – 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 inner 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.

What are the examples of glaucomas and their treatments?

Open angle glaucomas include:

  • Primary open angle glaucoma (POAG), the most common type of glaucoma, where there is primary failure of the internal drain of the eye. Treatments for POAG include eye drops/pills, SLT, cataract surgery, MIGS, or glaucoma surgeries.

  • Pigmentary glaucoma (PG) develops due to pigment clogging of the angle. In this condition, the iris is prolapsed backwards towards the lens. The posterior surface that contains pigment rubs off suspensions (zonules) that hold the lens in place. The pigment gets released and deposited inside the eyeball structures, including the drain. This leads to clogging and compromised fluid outflow. Areas of iris devoid of pigment have a characteristic appearance called “iris transillumination” defects. Pigmentary glaucoma is treated medically, with SLT (to unclog the drain from pigment), LPI (to lift the iris away from the zonules and decrease the pigment release), cataract surgery (to decrease contact between the zonules and iris), or glaucoma surgeries.

  • Traumatic glaucoma results from trauma-related damage of the drain. Lasers are usually not effective in this type of glaucoma. Patients are treated medically or surgically.

  • Steroid-induced glaucoma can develop due to long-term use of steroids. Treatment is like for POAG. Patients respond better to SLT.

  • Normal tension glaucoma is called so because the optic nerve develops characteristic damage despite normal eye pressure. Treatment is like for POAG.


Angle closure glaucomas include:

  • Acute angle closure attack develops due to a sudden closure of the angle and rapid buildup of eye pressure resulting in blurry vision, eye redness, pain, tearing, headaches, nausea, and vomiting. It is a sight-emergency situation which requires prompt treatment to prevent blindness.

  • Plateau iris syndrome causes chronic angle closure glaucoma. This is characterized by gradual closure of the angle due to slow and painless eye pressure buildup. In this condition, the ciliary muscle, a structure behind the iris, is enlarged. As it moves forward, it pushes the iris towards the cornea, resulting in narrowing of the angle. In addition, with age, we develop cataracts (cloudiness of the clear lens). The ciliary muscle and cataract together may push the iris towards the cornea even further, resulting in progressive, gradual eye pressure buildup and damage to the optic nerve. Sometimes the eye pressure may build up rapidly and cause acute angle closure attack. This condition is usually treated with laser procedures or cataract/goniotomy surgeries. Medical treatment is supplemental.

  • Pseudoexfoliative glaucoma (PXG), where the eye produces a dandruff-like or pseudoexfoliative protein, which clogs the angle. Initially, the angle is opened. With time, the zonules that hold the lens in place become weak. In addition, the lens degenerates and becomes cloudy leading to cataract development. As a result, the stressed zonules cannot keep the lens in place, the lens displaces forward and pushes the iris towards the cornea, resulting in angle narrowing or closure. The treatment is like POAG. LPI may be used to manage angle closure prior to cataract surgery.

  • Inflammatory glaucoma results from the angle being clogged by inflammatory cells. With time, the opened angle becomes closed due to development of inflammatory adhesions between the iris, lens and cornea, leading to fluid outflow impediment. It is important to identify the cause of inflammation and treat the cause. This is in addition to using medical, LPI/Iridoplasty, or glaucoma surgery option​

  • Neovascular glaucoma (NG) results from angle being affected by new blood vessel growth. The frequent causes of neovascular glaucoma include uncontrolled diabetes, central retinal vein or artery occlusion, and branch retinal vein or artery occlusion. In this situation, the lack of blood supply to the eyeball stimulates new blood vessel growth inside the eyeball including inner drainage. Initially new blood vessels act as a physical barrier to fluid outflow through the open-angle. And later, when the blood vessels regress, they facilitate formation of adhesions between the iris and cornea, resulting in angle closure. In addition to managing glaucoma with eye drops/pills/tube shunt, it is important to treat the underlying cause as well.

Disclaimer: This information is not comprehensive to cover all your ophthalmology needs. Call the office to book an appointment to discuss your condition with Dr. Hennen.


Eyecare MPLS: Stella Hennen, MD, MSPH

Lake Calhoun

Executive Center

3033 Excelsior Blvd #205

Uptown, Minneapolis, MN 55416

Phone: 612-470-9871

Fax: 612-470-9881


Monday.         9:00 am - 4:00 pm

Tuesday.         9:00 am - 4:00 pm

Thursday.       9:00 am - 4:00 pm

Friday.             9:00 am - 3:00 pm

Saturday.       Closed

Sunday.         Closed


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