Glaucoma is a progressive eye disease that damages the optic nerve. Because the optic nerve transmits information from your eye to your brain, glaucoma can result in a gradual, irreversible loss of vision and may eventually lead to blindness. Although there are different types of glaucoma, high intraocular pressure (IOP) — also referred to as high eye pressure — is often present and is one of several risk factors for glaucoma. However, many patients with glaucoma do not have high IOP – which is why a comprehensive eye exam, including an examination of the optic nerve, is important for early diagnosis.
What Is Primary Open-angle Glaucoma?
Primary open-angle is the most common type of glaucoma. With open-angle glaucoma, the disease is characterized by increased eye pressure, known as intraocular pressure (IOP). Over time, this pressure can damage the optic nerve, causing an irreversible loss of vision. In some cases, damage can occur due to other factors, even though eye pressure may be normal.
The Role of Fluid in Your Eye
Your eye produces a clear fluid called aqueous humor in the chamber at the front of the eye. This fluid nourishes nearby tissues and helps to maintain proper pressure balance within the eye. In a healthy eye, it flows through a tiny drain called the trabecular meshwork in the front of the eye. Whether this pressure is normal or elevated, it is not something you can ordinarily feel.
When the Fluid Backs Up
For reasons that are not fully understood, the drainage canal can become clogged over time. Other times, your eye can produce too much fluid, which can result in elevated intraocular pressure (IOP). As the normal level of fluid builds up, it can trigger an increase of pressure within the eye. This condition, called high IOP can lead to open-angle glaucoma. Open-angle glaucoma represents at least 90% of all glaucoma cases – making it the most common form of the disease.
Eye Pressure and Your Optic Nerve
As pressure builds within the eye it can damage the sensitive optic nerve – which connects the eye to the brain, and is necessary for healthy vision. There are no early warning signs for this damage. In fact, it may take several years before there is noticeable loss of sight – which typically starts on the periphery (sides) of your vision, and with time, can include your central vision. For this reason, and because damage to the optic nerve is irreversible, it’s important to have regular eye exams.
So When Do You Have Glaucoma?
Having increased eye pressure may mean that you are at risk for glaucoma, but not necessarily that you have the disease – which is determined when there is damage to the optic nerve. Even those with what is considered normal IOP can also develop glaucoma. Fortunately, there are treatment options that can control eye pressure, which may reduce the rate and extent of additional damage to the optic nerve.
What is Closed-angle Glaucoma?
Closed-angle glaucoma, also called angle-closure glaucoma, acute glaucoma, or narrow-angle glaucoma, is glaucoma that is marked by a drainage angle that’s narrower than the normal. It tends to occur in people of Asian heritage and those who are farsighted because their eyes’ anterior chambers are narrower than normal. However, some patients without these risk factors go on to develop closed-angle glaucoma as well.
The anterior chamber is the compartment between the cornea and the iris that contains the trabecular meshwork, which is a mesh-like drainage system of canals that help the eye’s nourishing fluid (the aqueous humor) to pass out of the eye. This meshwork is in the compartment formed between the cornea and the iris.
If that angle is too narrow, fluid can’t drain efficiently. The thickening of the lens, which happens with age, makes the angle even narrower. And the fluid that is prevented from draining creates more of a problem by building pressure behind the iris — in addition to the elevated IOP — narrowing that angle even more. If the pressure gets high enough to push the iris against the trabecular meshwork, it blocks drainage completely, and the result is an angle-closure glaucoma attack. Also known as acute glaucoma, this is a medical emergency. Symptoms may include headaches, eye pain, nausea, rainbows and starburst around lights at night, and blurred vision.
A standard test during a comprehensive eye examination can determine whether you have narrow angle glaucoma. To treat this condition, a small piece of the iris is surgically removed to unblock the drainage canals. This can be done either with laser or conventional surgery.
Are You Experiencing Symptoms of Glaucoma?
Open-angle glaucoma, the most common type, is called “the silent thief of sight” because most people have no symptoms until damage is done. Once you notice vision loss, the damage may already be severe3A and permanent.
How Vision Loss Typically Occurs
1. Vision loss starts in the periphery or side and can be hard to notice. Even after you lose some side vision, you still may not realize it. Some people may compensate by turning their head without knowing it.
2. Unlikely in the early stages, as glaucoma progresses, you may notice that you’re missing things to the side and are developing tunnel vision.
3. Over time, vision decreases until there’s nothing left. That’s why early detection is so important.
When Do Symptoms Indicate a Medical Emergency?
When the drainage canals are suddenly blocked, eye pressure rises quickly. This is a medical emergency. Symptoms may be on and off at first, or get worse steadily. They may include:
• Sudden, severe pain in one eye
• Decreased or cloudy vision
• Nausea and vomiting
• Rainbow-like halos around lights
• Red eye
• Eye feels swollen
• Pain above the eyebrows
Who Develops Glaucoma?
Anyone can develop glaucoma, but certain factors put you at higher risk:
• High intraocular pressure (IOP)
• Family history of glaucoma
• African or Latino descent
• Severe Myopia (Nearsightedness)
• Regular use of oral steroids, topical steroids or cortisone medications over a long period
• Over age 60
• Diabetes
• Hypertension (high blood pressure)
• A thin cornea, which may cause your doctor to underestimate your intraocular pressure (IOP)
If you have any of these glaucoma risk factors, see your eye care professional regularly for glaucoma prevention and early diagnosis.
Treatment Options for Patients with Glaucoma
There is no treatment for glaucoma. However, there are two main types of treatments intended to lower intraocular pressure, a modifiable risk factor for glaucoma: medication and surgery.
Open-angle glaucoma treatment often starts with prescription eye drops to help lower IOP. Your doctor may prescribe a single type of eye drops or a combination of types. You may need more than one medication to keep your eye pressure low enough. Your doctor may change a medication if it causes side effects. If eye drops do not lower intraocular pressure enough, your doctor may prescribe surgery, but this doesn’t necessarily mean you won’t have to take eye drops any more, and surgery may need to be repeated. While surgery can lower eye pressure, it cannot restore lost vision.
Closed-angle glaucoma is most often treated with surgery.
When is Glaucoma Surgery Performed?
Several types of glaucoma surgery are used to treat open-angle glaucoma and closed-angle glaucoma. Open-angle glaucoma is generally treated with medication first. If necessary, surgery may be repeated a number of times. Glaucoma surgery is usually the first choice for closed-angle glaucoma.
The two main types of surgical treatment are laser and conventional surgery.
Laser Surgery
There are different types of laser surgery, but they all apply a small beam of light to the eye’s drainage system to help fluid flow out of the eye. When laser surgery does not lower eye pressure enough, or the pressure starts to rise again, the doctor may recommend conventional surgery.
Conventional Surgery (Trabeculectomy)
A conventional surgical procedure called Trabeculectomy, or filtration surgery, is used when medications and laser therapies haven’t lowered your intraocular pressure (IOP) enough, or when your eye pressure rises again after surgery. A small instrument makes a passage in the white part of the eye (sclera) to give eye fluid a new place to drain.
Alternatives to Trabeculectomy
There are many different ways to lower intraocular pressure (IOP). If you’re a candidate for surgery, you may want to discuss the alternatives with your doctor. Here are a few of them:
Tube Shunts – small tubes made of silicone or other materials are surgically inserted into the eye to provide an alternative pathway for fluid (aqueous) to drain.
Filtration Devices – uses a stainless steel shunt to divert fluid.
Glaucoma surgery for most of our Colorado Springs patients is performed at the Peak Surgery Center, located at our 9320 Grand Cordera Parkway building in Colorado Springs. This specially designed surgical center is dedicated exclusively to eye surgery and is equipped with the most advanced eye surgery instrumentation and equipment available.
For more information about glaucoma and/or glaucoma surgery, please call 719-258-1240 or email our ophthalmologists to schedule your initial consultation.