Glaucoma Service
Glaucoma is a family of diseases that affect pressure in the eye, causing damage to the optic nerve. Damage to the optic nerve may result in loss of vision. Glaucoma is one of the leading causes of blindness in the United States. Most forms of glaucoma do not produce symptoms until vision is already severely damaged. But if diagnosed early, the disease can be controlled and permanent vision loss can be prevented.

What are the common types of glaucoma?

  • Acute Angle Closure Glaucoma: sudden closure of the eye’s drainage system, with a dramatic increase in intraocular pressure.
  • Chronic Angle Closure Glaucoma: slow, progressive closure of the eye’s drainage system
  • Primary Open Angle Glaucoma: the most common form of glaucoma, in which the drainage angle is open but does not allow fluid to drain adequately.
  • Pseudoexfoliation Glaucoma: fibrillary material produced in the eye clogs the drainage system.
  • Pigmentary Glaucoma: pigment released from the iris clogs the drainage system.
  • Angle Recession Glaucoma: caused by damage to the drainage system from recent or old injury
  • Neovascular Glaucoma: disorders such as diabetes or blockage of retinal veins cause blood vessels to proliferate on the iris and in the eye’s drainage structures.
  • Congenital Glaucoma: the eye’s drainage system forms abnormally during development.

What are the risk factors for glaucoma?
Although glaucoma is most common in adults over the age of 40, susceptibility is not determined by age alone. There is a genetic component, and those with a family history of the disease, as well as African-Americans, are at increased risk. Studies have shown people at greater risk for glaucoma may fit one or more of the following criteria:

  • are over the age of 60
  • are African-American over age 40
  • have a family history of the disease
  • have elevated intraocular pressure
  • are nearsighted

Since early detection is critical to avoiding permanent loss of vision, people with any of these risk factors should have regular examinations by an ophthalmologist every one or two years.

People in the general population should have a glaucoma evaluation every two or three years after the age of 40, and every one or two years after the age of 60.

What is involved in a glaucoma evaluation?
We perform a comprehensive glaucoma screening that consists of three non-invasive, pain-free procedures:

  • Measurement of intraocular eye pressure (IOP). Elevated IOP is a major risk factor for the development of glaucoma. Optic nerve damage becomes more likely as the IOP increases.
  • Assessment of the optic nerve. A slit lamp microscope is used to determine whether or not there are changes in the optic nerve.
  • Evaluation of a patient’s visual field. Glaucomatous damage produces characteristic defects in the visual field.

What is the treatment for glaucoma?
Glaucoma treatment seeks to decrease intraocular pressure and prevent damage to the optic nerve. Different types of glaucoma require different therapies. At the beginning of treatment, the doctor will generally recommend medication or a combination of medications for the specific condition. Therapies may include:

  • Eye drops to reduce intraocular pressure. Several different classes of glaucoma medications are available to provide pressure reduction including beta-blockers, prostaglandin analogues, alpha adrenergic agonists, miotics, and carbonic anhydrase inhibitors. These medications work by either reducing the rate at which fluid in the eye is produced or increase the outflow of fluid from the eye.
  • Laser treatment to open the drainage angle and reduce intraocular pressure.
  • Surgery to create a new passage for fluid drainage. Surgery is usually reserved for cases that cannot be controlled by medications and/or laser treatment.

Glaucoma operations have been shown to be safe and effective surgical treatments. The two main types of surgical procedures are tube shunt surgery and trabeculectomy. Both tube shunt surgery and trabeculectomy lower the intraocular pressure by creating a route for aqueous fluid to drain out of the eye.

Drainage implants --- A tube inserted into the eye shunts aqueous fluid to a silicone plate that is attached to the sclera (the white portion of the eye).

Trabeculectomy --- An opening, surgically created under a trap-door incision in the sclera, allows aqueous fluid to drain. Anti-scarring medications such as mitomycin or flurouracil are commonly applied at the operation site to reduce scarring that could close the trap door.

Frequently Asked Questions About Glaucoma

Is blindness due to glaucoma preventable?
Regular examinations are the key to preventing loss of vision due to glaucoma. Although there is no way to reverse damage, if glaucoma is diagnosed and treated early, blindness is almost always preventable.

What are the symptoms of glaucoma?
Although the blindness associated with this disease is preventable, more than one million people in the United States have some glaucoma-related vision loss. In most cases, glaucoma is asymptomatic (has no symptoms). By the time an individual experiences decreased vision, the disease is frequently in its latter stages. Since early warning signs of glaucoma are rare, it is important --- especially for those at risk --- to have medical eye examinations at appropriate intervals, as described in this section.

Symptoms depend on the type of glaucoma the individual has.

  • Those who have chronic glaucoma may not be aware of any symptoms because the disease develops slowly and patients rarely notice loss of peripheral vision.
  • Those who have an acute form of glaucoma may develop severe symptoms because ocular pressure rises quickly and they may experience:
    • Blurred vision, especially at night
    • Halos or rainbows around lights
    • Severe headaches or eye pain
    • Nausea
    • How does glaucoma affect the eye?

The eye has an internal pressure created by production of a clear fluid called aqueous humor. This fluid circulates through the eye and exits through the anterior chamber angle and ultimately drains into the blood stream. In glaucoma, the aqueous humor outflow is obstructed, resulting in increased eye pressure and, eventually, optic nerve damage.

What research is being conducted for glaucoma patients?
Medical and surgical treatments are being researched. Many national clinical trials are ongoing or have been completed, including the Ocular Hypertension Study (OHTS), the Advanced Glaucoma Intervention Study (AGIS), the Collaborative Normal Tension Glaucoma Study (CNTGS), and the Collaborative Initial Glaucoma Treatment Study (CIGTS).

New medical treatments for glaucoma that affect blood flow to the optic nerve, intraocular pressure, and survival of retinal ganglion cells are being investigated. Although decreasing intraocular pressure is the only treatment shown to slow progression of most forms of glaucoma, other treatments to help retinal ganglion cells survive are actively being tested. Combinations of different pre-existing glaucoma medications are in clinical trials as well.

Different technologies are being compared for the early detection of glaucoma including retinal nerve fiber and other structural analysis through techniques such as optical coherence tomography. Different functional tests of retinal ganglion cell function including short wavelength automated perimetry (SWAP) are also actively being studied for early detection of visual field loss.

Surgical techniques such as selective laser trabeculoplasty (SLT) and non-penetrating types of filtering surgeries are being compared to conventional treatments such as argon laser trabeculoplasty, trabeculectomy and drainage implants. New glaucoma drainage implants that are possibly easier to implant or provide better pressure control are in the design and clinical trial phases of development.

Probably one of the most exciting areas of glaucoma research is in the area of genetics. Studies of families with glaucoma have identified several genes involved in glaucoma and the function of these genes and the search for more genes are ongoing. These studies will hopefully provide scientists with new targets to treat glaucoma in addition to intraocular pressure and possibly allow for genetic screening for patients at risk of developing glaucoma.

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