Glaucoma is a disease in which the pressure in the eye leads to optic nerve damage. The optic nerve is what carries light signals from the eye to the brain. Damage to the optic nerve can lead to blindness. 3 million Americans are estimated to have glaucoma, and half of the patients with glaucoma do not realize they have the disease. There are generally no symptoms in the early stages. The loss of vision can be gradual, which makes glaucoma a silent disease. If left untreated, blindness may occur. Fortunately, there are glaucoma treatments to help prevent vision loss.
The most common types of Glaucoma are:
- Open-Angle Glaucoma
- Closed-Angle Glaucoma (Narrow-Angle or Angle-Closure)
- Secondary Glaucoma
Primary open-angle glaucoma (POAG) is the most common form of glaucoma in the U.S. There is fluid in the eye called aqueous, which drains through the trabecular meshwork and out of the eye. When the fluid drainage is less than the fluid production, intraocular pressure (IOP) increases and leads to glaucoma damage. Some people may have higher-than-average IOP and not have signs of vision loss or glaucoma. We call this ocular hypertension. Conversely, other patients may have low-to-normal IOP and yet still develop optic nerve damage called normal-tension glaucoma (NTG).
Risk Factors for Glaucoma Include:
- Over 60 Years Old
- Family History
- African American
- Myopia (Nearsightedness)
- High IOP
- Eye Injury
- Steroid Use (Particularly Eye Drops)
Glaucoma is a treatable disease, and with early detection, blindness is preventable. Your vision is important. Schedule an eye exam today.
Narrow-Angle or Angle-Closure Glaucoma
The fluid in the eye drains through the angle, which is the space between the iris and the cornea. If the angle is narrow or closed, the fluid drainage is obstructed, and pressure can build up in the eye. This can happen quickly, as with acute angle-closure glaucoma, or over time with chronic angle-closure glaucoma. Patients with increased risk include hyperopes (farsightedness) and Asian ancestry. Over-the-counter decongestants and certain medications can increase the risk of angle-closure glaucoma. Check with your eye doctor before taking such medications.
Signs of Acute Angle-Closure Glaucoma:
- Blurred Vision
- Haloes Around Lights
- Nausea and Vomiting
Laser Peripheral Iridotomy (LPI)
Fortunately, angle-closure glaucoma is preventable for those with narrow angles when detected early. A laser peripheral iridotomy (LPI) is most commonly performed to create a new drainage pathway by creating a small opening in the iris. If cataracts and visual symptoms are present, cataract surgery can also be a method for resolving the narrow angle. Both LPI and cataract surgery are outpatient procedures covered by Medicare and insurances.
Some patients develop glaucoma as a result of external pressure on the eye (i.e., from a tumor), inflammation, diabetes, medications, or eye drops. These forms of glaucoma are considered secondary glaucoma and treated differently from normal primary open-angle glaucoma.
The most common treatment for glaucoma is medication drops. These medications help lower the IOP by decreasing aqueous production or increasing aqueous drainage. Eye drops will not affect or improve the vision, but they are used to reduce progression of glaucoma and vision loss. Compliance and daily use of glaucoma drops are crucial.
It is important to discuss with your eye doctor what medical conditions you have as this may affect which eye drop is recommended for you. You should also inform your doctor of all oral or systemic medications you take as some may affect your eye pressure.
Laser and surgery are options for those who have exhausted or failed glaucoma medical therapy. Some patients have difficulty taking or remembering to take their glaucoma drops. If eye pressure is uncontrolled despite maximal medical therapy, laser or surgery is the next line of treatment. Laser is also a first-line option for patients with early or mild glaucoma who elect this therapy over using drops.
Selective Laser Trabeculoplasty (SLT)
Selective laser trabeculoplasty is a laser procedure performed to lower the eye pressure. It works by targeting specific cells in the trabecular meshwork, which is the main drainage pathway for the aqueous. This outpatient procedure has been shown as effective for lowering eye pressure without systemic side effects or ocular irritation that may be seen with glaucoma drops. SLT is covered by Medicare and other insurances.
Trabeculectomy is the traditional surgery performed for glaucoma in patients with progressive disease despite medical and/or laser therapy. The procedure is performed by creating an ostomy or opening in the sclera (white layer of the eye) for the aqueous to filter through to a reservoir. The reservoir forms a bleb or bump on the conjunctiva (clear membrane overlying sclera). Additionally, an express shunt can be inserted at the time of trabeculectomy in order to facilitate flow and decrease complications, such as low pressures following surgery. Many patients who undergo trabeculectomy gain independence from glaucoma medications and drops.