Glaucoma - What You Need To Know


Primary Open-Angle Glaucoma (POAG). Primary glaucoma is an eye disease in which the pressure inside your eyes increases enough to damage the nerve fibers in your optic nerve and cause vision loss. The increase in pressure happens when the passages that normally allow fluid in your eyes to drain become clogged or blocked. Glaucoma often is called the "silent thief of sight," because most types typically cause no pain and produce no symptoms until noticeable vision loss occurs.
Progressive side vision loss in untreated glaucoma.

Glaucoma is one of the leading causes of blindness in the U.S. It most often occurs in people over age 40. People with a family history of glaucoma, African Americans, and those who are very nearsighted or diabetic are at a higher risk of developing the disease.

Acute Glaucoma. A less common form of glaucoma is acute angle-closure glaucoma, symptoms can occur suddenly and can include blurry vision, halos around lights, intense eye pain, nausea and vomiting. If you have these symptoms, make sure you see an eye doctor or visit the emergency room immediately so steps can be taken to prevent permanent vision loss.

Normal-tension glaucoma. Like POAG, normal-tension glaucoma (also termed normal-pressure glaucoma, low-tension glaucoma or low-pressure glaucoma) is an open-angle type of glaucoma that can cause visual field loss due to optic nerve damage. But in normal-tension glaucoma, the eye's IOP remains in the normal range. The cause of normal-tension glaucoma is not known. But many doctors believe it is related to poor blood flow to the optic nerve. Normal-tension glaucoma is more common in those who
are Japanese, are female and/or have a history of vascular disease.

Examination For Glaucoma - Should Include:

  • History evaluation. The doctor or staff will ask questions about your medical and personal history, as well as your family's medical history.
     
  • Measurement of intraocular pressure (IOP) using an instrument called a tonometer (see photo below).
     
      Some tonometers measures the intraocular pressure
    using a pressure-sensitive tip placed gently against the
    eye (Goldman tonometer). Short-acting anesthetic drops
    are normally used to numb the eye with this instrument.

    Other tonometers measure the intraocular pressure by
    directing a brief puff of air gently onto the eye. "air-puff" tonometers are frequently used as screening instruments
    since no drops are required.

    "air-puff" tonometer

    		    

  • Examination of the optic nerve with an ophthalmoscope (see photo below).
     
      ophthalmoscopy - The doctor uses drops to dilate
    (widen) the pupil so he or she look at your optic nerves
    using a special instrument called an ophthalmoscope.
    This allows the doctor to look for damage to your optic
    nerves. Various types of ophthalmoscope may be used. The A binocular ophthalmoscope gives the doctor a 3-D
    view of your eye's interior and provides additional
    diagnostic information.
     
     

    Binocular ophthalmoscope

    		    

  • Examination of the visual fields (see photo below).
     
      A perimeter is used to test your visual field. The
    visual field includes both your central and side vision.
    This test can tell the doctor how much vision has
    been lost, even if you notice no impairment. Changes
    due to glaucoma usually follow a particular diagnostic pattern. Other patterns of visual field loss indicate
    the existence of possible neurological diseases,
    adding significantly to the value of this test.

    Perimeter

    		    

Some of these tests may not be necessary for every patient but other tests may be added, if glaucoma is suspected or if glaucoma damage increases over time. In some cases, your doctor may employ additional high-technology instruments (OCT, GDX, SLP, etc.) to help asses your eye health.

Note: Because your eye may be dilated during your exam, you may want to bring sunglasses with you to your appointment. Dilation can make your eyes extra sensitive
to light for a short time after your exam.

Who is at Risk?

Everyone should be concerned about glaucoma and its effects. It is important for each of us, from infants to senior citizens, to have our eyes checked regularly. Early detection and treatment of glaucoma is the only way to prevent vision impairment and blindness. There are a few conditions related to this disease which tend to put some people at greater risk. This may apply to you if:

  • You are over 45 and have not had your eyes examined regularly

  • Someone in your family has a history of glaucoma

  • You have abnormally high intraocular pressure

  • You are of African descent

  • You have diabetes

  • You are highly myopic (nearsighted)

  • You have regular, long-term steroid/cortisone use

  • You have a previous eye injury
     

Glaucoma treatment. Glaucoma cannot be prevented but if diagnosed and treated early, it can be controlled. Treatment can involve glaucoma surgery, lasers or medication, depending on the severity. Eye drops with medication aimed at lowering IOP usually are tried first to control glaucoma.

For more information on glaucoma, you may wish to visit AllAboutVision.com.


Sources:
1. National Eye Institute   Back to Top
2. American Optometric Association    
3. All About Vision    
     
Vision & Health Newsletter courtesy of:
 		  
Dr. Philip Smith & Associates
1855 1st Ave #100
San Diego, CA 92101

619-297-4331