What is commonly called “glaucoma” is actually a family of diseases. The common feature of this disease family is progressive atrophy (degeneration) of the nerve of the eye (the optic nerve), which initially leads to loss of peripheral (side) vision. Total vision loss can occur later in the course of the disease.
In a healthy eye, a clear fluid called aqueous humor flows in and out of the anterior chamber in the front of the eye, nourishing surrounding tissue. The fluid exits the chamber through the drainage angle, where the cornea and the iris meet. It drains through spongy tissue called the trabecular meshwork before leaving the eye.
If the eye is unable to properly drain fluid, the pressure inside the eye (i.e., intraocular pressure) can rise. This gradually threatens the health of the optic nerve, which is a bundle of nerve fibers that transmit information from the eye to the brain.
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There are several different types of glaucoma. In cases of open-angle glaucoma, which is the more common form of the disease, the drainage angle remains open, yet the eye is not able to drain fluid as well as it should. It is as if the drainage angle is similar to a clogged drain. Open-angle glaucoma progresses very slowly and painlessly. Sadly, this occurs with either no symptoms or very few in the early stages of the disease, and by the time patients notice a problem, significant vision loss may have already taken place.
In the rarer form of the disease, angle-closure glaucoma, the drainage angle becomes completely blocked. This can happen if the eye’s iris is too close to the drainage angle. When the drainage angle becomes blocked, intraocular pressure spikes very rapidly, causing noticeable symptoms. This is considered an emergency and requires immediate medical intervention to avoid blindness.
In the majority of cases, glaucoma is associated with higher intraocular pressures (pressure inside the eyeball), although sometimes glaucoma damage can occur with seemingly “normal” or even low eye pressures.
Detecting Glaucoma
As mentioned, with cases of open-angle glaucoma, there are very few obvious visual symptoms at first. Gradually, blind spots can develop in peripheral, or side, vision. Usually open-angle glaucoma is left undetected until the damage is very severe. Increases in intraocular pressure can be detected during eye exams, which is why ophthalmologists encourage older adults at a higher risk of developing glaucoma to have regular exams.
On the other hand, angle-closure glaucoma develops quickly, causing symptoms that can include the following:
Very blurry vision
Severe eye pain
Nausea and vomiting
Headache
Rainbow-colored rings or halos around lights
Glaucoma Testing
Early detection of glaucoma is important to preventing vision loss to the disease. A comprehensive evaluation for glaucoma with the Access Eye doctors includes the following steps:
Dilated eye exam: The patient’s pupils are dilated (opened) so the doctor can take a magnified view at the internal structures of the eye. During the exam, the doctor uses a special magnifying device to look at the optic nerve’s shape, size, color, depth and vessel for any signs of damage due to glaucoma. The doctor may take photographs of the optic nerve, which are useful for monitoring the progression of glaucoma.
Visual field test: The visual field test determines whether the patient has lost any peripheral vision to glaucoma (if so, the test can measure how much and exactly where vision has been lost).
Eye pressure check: Also known as tonometry, this test determines the pressure inside the eye by measuring the force with which the eye pushes back against a sensor.
Gonioscopy: A special mirror allows the doctor to examine the area where the cornea meets the iris internally, which is called the “angle.” Whether the angle is wide open or closed determines the basic type of glaucoma (open angle glaucoma vs. angle closure glaucoma).
Pachymetry, or corneal thickness test: The thickness of the cornea can affect eye pressure readings. For any given pressure inside the eye, the thicker the cornea, the higher the measured pressure will be during the eye pressure check.
Glaucoma tests are non-invasive and painless.
Treatment and Management of Glaucoma
Practically speaking, efforts to treat glaucoma are focused on lowering intraocular pressure. This can be accomplished by reducing the amount of fluid the eye produces or increasing the amount of fluid that exits the eye.
In broad terms, the treatment types available are:
The daily use of eyedrops to lower the amount of aqueous fluid the eye makes or help fluid drain through the drainage angle.
Laser procedures, which involve using a laser to help aqueous drain from the eye.
Laser trabeculoplasty improves the way the drainage angle works, helping fluid flow out of the eye properly.
Laser iridotomy creates a tiny hole in the iris to help fluid flow through the drainage angle.
Traditional surgical procedures create new openings through which aqueous fluid can leave the eye.
Trabeculectomy involves the creation of a small flap in the white of the eye and a pocket in the conjunctiva; the fluid exits the eye through the flap and collects in the pocket.
Minimally invasive glaucoma surgery [MIGS] is a relatively new and exciting area of glaucoma treatment involving the implantation of tiny devices to create new ways for fluid to drain from the eye.
Viscocanalostomy reroutes aqueous fluid from the trabecular meshwork through a newly created channel.
At Access Eye we offer treatments within each category. When appropriate, we can combine two different treatment modalities, such as laser or traditional surgery with the use of medicated eyedrops, for the best results. In more advanced cases, we can utilize a number of referral resources.
Factors that increase the risk of glaucoma include the following:
Being over the age of 60
African-Americans over the age of 40
Having diabetes
Having a family history of glaucoma
Having a history of trauma to the eye
Individuals who are at an increased risk of getting glaucoma are encouraged to schedule eye exams to check for signs of the disease. The earlier the disease is caught, the easier it is to protect against vision loss.
It depends on the type of glaucoma. Open-angle glaucoma, which is far more common in the U.S., typically develops slowly and generally does not cause pain. Angle-closure glaucoma, on the other hand, develops and progresses rapidly and can cause severe eye pain, headaches, nausea and vomiting. Individuals who experience these symptoms should see a doctor immediately to reduce the risk of permanent vision loss.
There are at least five categories of medications available for glaucoma. They are generally applied as eyedrops one to three times per day. Generally the treatment is continued indefinitely.
The most common treatment is called laser trabeculoplasty, which can be done with the argon laser (ALT) or the more recent selective laser (SLT).
During SLT, the trabecular meshwork (essentially the filtering tissue in the angle of the eye) is illuminated with a special laser, and the laser energy is specifically absorbed by the pigment in this particular tissue. SLT ultimately eases the passage of fluid through the trabecular meshwork, hence lowering the eye pressure
Alternate drainage pathways can be created either with modifications to the natural components (trabeculectomy), external placement of drainage devices or modifications to the existing internal filtration of the eye with new treatments called Minimally Invasive Glaucoma Surgeries (MIGS).
MIGS has been a recent leap in treatments of milder or moderate forms of glaucoma and can be performed either as standalone procedures or more commonly combined with cataract surgery. One exciting example of a MIGS device is called the iStent, which is a microscopic device inserted into the natural internal drainage system of the eye, bypassing the trabecular meshwork. In the hands of an experienced surgeon, the device can be implanted as an add-on procedure to cataract surgery with relative ease, minimal further manipulations to the eye and very little surgical time added.
The cost of glaucoma treatment depends on the specific treatment plan. For instance, the cost of medicated eyedrops differs from the cost of laser treatment. For more information about glaucoma treatment costs, please schedule an appointment with the team at Access Eye.
Currently there is no cure for glaucoma. However, the team at Access Eye offers a range of treatments to slow the progression of the disease and prevent or delay vision loss.
Many of our patients have been coming to us for management of their glaucoma over decades and the wealth of practical experience we have developed in this arena has enabled us to dedicate a large portion of our practice to treating this disease. Vision lost to glaucoma is, for the most part, vision lost forever. This makes early diagnosis and treatment the key to management of this disease.
