Glaucoma
EYE CENTER of MISSOURI

                      GLAUCOMA

    Glaucoma is a group of diseases characterized by increased intra
    ocular pressure resulting in damage to the optic nerve and retinal
    nerve fibers.   Any damage to the optic nerve causes blind spots and
    they are usually not reversible.  If Glaucoma is left untreated or is
    poorly controlled, these blind spots get bigger over time and
    eventually can cause total blindness. Purpose of the treatment is to
    prevent any further damage and blindness. Early detection is the key
    to a successful management.
            
                                       
 TYPES OF GLAUCOMA

    There are several types of glaucoma.   The most common type is
    called open angle glaucoma.  In this type,  the pressure builds up due
    to poor drainage of  the aqueous fluid from the eye. There is second
    type of Glaucoma called Angle Closure Glaucoma.  In this type, the iris
    (colored portion) blocks the drainage pores, so the aqueous or the
    eye fluid does not have free access to the drainage pores, which
    again causes the pressure to rise.  Sometimes both types can exist
    in the same eye.   Besides these two, there are several others but
    they are less common types.                                     

    Glaucoma effects every segment of the population but is more
    prevalent in people over age 50, African Americans , diabetics,  
    hypertensives, family history of this disease and people using
    steroids.                 
         
                     DIAGNOSIS

    In general , a diagnosis of Glaucoma is made
    by clinical examination of the optic nerve ,
    pressure measurements and examination of
    the  structure of the eye, especially depth of
    the anterior chamber (space between iris and
    cornea).  This space is deep in open angle
    glaucoma but becomes narrow in angle
    closure glaucoma. Pressure is usually higher
    than normal in about 90% cases but it may be
    normal.  Sometimes it may be difficult to
    detect very early changes in the optic nerve if
    the doctor is looking through a cataract or a
    cloudy cornea.

             TESTS FOR GLAUCOMA

                      VISUAL FIELD

    If glaucoma is suspected, a test called Visual
    Field test or Perimetry is done to see if blind
    spots have developed. If someone already
    has glaucoma, then this test is repeated
    periodically to see if the pressure control is
    adequate and blind spots are not worsening.
    Any deterioration of this test usually warrants
    more aggressive treatment.
         
             NERVE FIBER LAYER ANALYZER

    This test is done to look at the health of the
    optic nerves. Just like previous test, this is
    also repeated periodically to see if nerve is
    not deteriorating. There are several different
    machines available in the market for this
    purpose but most popular are called GDx and
    OCT. The eye center has both machines
    available.
          
                 COLOR PHOTOGRAPHS

    Photographs of the optic nerves may be taken
    to follow the progression of the disease.  
    These tests are repeated periodically to see if
    the disease is under control or progressing.

                      PACHYMETRY

  This is measurement of corneal thickness.

                      GONIOSCOPY

  This is assessment of drainage area.



    Glaucoma is very complex and several factors
    are considered in making a diagnosis and its
    treatment, including clinical examination along
    with test results as well as family history and
    other risk factors such as race and diabetes.
                                                         
                                                    TREATMENT


    Treatment of glaucoma depends on the type. Open angle is treated with the eye drops, sometimes
    combined with the use of lasers, to reduce the pressure in the eye so the damage to the optic nerve
    and vision can be stopped. Goal of the treatment is to bring the pressure down to a level that is
    tolerable by the optic nerve, and it varies from person to person. Most of the drugs used is to help
    reduce the formation of fluid inside the eye, called Aqueous Humor.  

                                                           
      MEDICAL TREATMENT

        Medical treatment of Glaucoma, using different types of eye drops is the most popular.
        There are several types of eye drops and they are used to control the pressure.
        In some cases more than one kind is necessary to achieve the target pressure.

                                                                            
LASERS

        Lasers are widely used in glaucoma management, mostly along with the drops.
    SLT laser helps open up the pores in the trabecular meshwork and improve drainage. This
    procedure is called Trabeculoplasty. Argon laser also does the same. At times both methods, drops
    and lasers may be used to reach the optimum level.

    Narrow angle type of glaucoma requires a different approach.  In this case, the lens behind the pupil
    is blocking the pupil and pushing the iris forward, which in turn blocks the porour drainage area
    called "Trabecular Meshwork" leading to pressure build up. A small microscopic opening in the
    peripheral iris is made with a laser called YAG laser. This allows the fluid to flow freely between two
    chambers of the eye  and improve drainage. This procedure is known as Iriditomy. These  types of
    lasers take only a few minutes to do and cause mild discomfort. Some people can have both  types
    glaucoma in the same eye  and need combined treatment. Many times this iridotomy may be
    required as preventive measure  if , on examination, anterior chamber is found narrow and iris is
    approaching the trabecular mesh work.  Risks from this procedure are minimal and far out weigh
    the benefits.

                                                                          
SURGICAL

    Surgical intervention is reserved for advanced cases where medical treatment and lasers have
    failed to achieve desired pressure level. Within surgical category, there are several procedures
    available to us. Each case is decided upon severity of the condition and risk tolerance.



       
Effect of high pressure on the optic nerve in glaucoma,
increase in the size of the central cup due to damage to
the nerve fibers
Visual field damage from glaucoma, such blind spots are permanent and will
increase in size, leading to blindness unless treated aggressively. In this
example, visual field constricts slowly from normal to a tunnel vision and
eventually vision is lost completely.
RESULTS OF A VISUAL
FIELD TEST DONE IN
THE OFFICE SHOWING
EXTENT OF THE BLIND
SPOTS
    NARROW  ANGLES  AND  NARROW  ANGLE  GLAUCOMA

    Eye ball is large spherical chamber and internally it is divided into two portions by the iris and the       
    lens,which is located just behind the pupil. The front portion,also called anterior chamber, is located  
    between the cornea in the front and the iris and the lens in the back. The bigger rear portion,also
    called  posterior chamber, lies behind the pupil. Also located behind the pupil is a tissue called
    CILIARY BODY   which produces small amounts of clear fluid all the time. This fluid essentially can not
    leave the eye except  from the anterior chamber, where another tissue, Trabecular Meshwork,  which
    is spongy in nature,  absorbs the fluid. This fluid has to travel to the anterior chamber through the
    pupil, there is no other way.

    In some cases,as we grow older,our natural lens inside the eye grows  in size and pushes the iris
    forward and starts to block the pupil as well.  Initially there is slight resistance to the outflow of the
    fluid but as the  condition worsens and lens becomes bigger in size, it causes more and more
    resistance. At the same time Anterior Chamber becomes  shallower as Iris is pushed forward by the
    growing lens. Besides shallow chamber, the angle between cornea and iris becomes narrow as well.
    This is known as Anatomically Narrow Angles in medical language. Trabecular meshwork , which is
    located in the angle between the iris and the cornea, also gets covered by the iris, resulting
    decrease in absorption of fluid out of the eye. These events eventually cause rise in intra ocular
    pressure, also known as Narrow Angle Glaucoma. It can be associated with damage to the optic
    nerves and vision loss as well, depending on duration and severity of the problem.

    Narrow Angle Glaucoma usually develops slowly over the years as the lens which causes this
    problem grows slowly, condition being  chronic in nature. However at times in an eye with shallow
    anterior chamber  and narrow angles the lens may block the pupil suddenly, raising the pressure to a
    dangerous level and causing sudden loss of vision. This is known as Acute Angle Closure Glaucoma.
    It is quite painful and visual loss is permanent if not treated immediately.

                                                                         IRIDOTOMY

    Anatomically Narrow Angles, when detected during the examination are treated with a laser, in which
    a small tiny hole is made in the iris so the fluid can flow to the anterior chamber easily, bypassing the
    pupil. Procedure is called IRIDOTOMY and is done in the office and is quick. It is done as a
    prophylaxis to prevent future damage.
                                     
    The benefits far outweigh the side effects or minimal discomfort that it causes. If Narrow Angle
    Glaucoma develops or is already present, in addition to the laser, eye  drops may be necessary to
    bring pressure down to a tolerable level. Rare cases may require surgery to control pressure and
    preserve vision.
                                                                         

                                                                       GDX
                                                                                         
    GDx Nerve Fiber Analyzer is a scanning laser system that detects early glaucoma
    by measuring the thickness of the retinal nerve fiber layer.
    GDX has a database containing bilateral retinal-verve fiber measurements on
    hundreds of normal subjects. The database  compares patients' scans with normals
    matched for age, race and gender and generates a color printout of the results.

    The GDx is capable of identifying early damage to the optic nerves and in such cases
    treatment can be started  before patients  have visual field loss from glaucoma. Test is
    done when glaucoma is suspected and periodically repeated to see if the progression
    has been stopped.
Moderate nerve
fiber layer loss
and associated
visual field  
        
Advanced
nerve fiber
layer loss and
associated
visual field


A look at GDX report
Left side shows
extensive nerve
fiber layer loss,  
right side is normal.
St. Louis STL


3535 SOUTH JEFFERSON
ST. LOUIS, MO 63118                     PHONE 314-771-3000
                                     
                                          TRABECTOMY

This is one of the newest in surgical treatment options for Glaucoma management and is least
invasive. Results are modest and complications are minimal. In this procedure, which is done in
a hospital outpatient setting, instrument called Trabectome is used to open up trabecular
meshwork or drainage area which relieves the pressure inside the eye. Procedure itself only
takes few minutes to perform and discomfort is mild.

                                      TRABECULECTOMY

In this procedure, a small opening or "window" is created to allow the fluid from the eye to drain
into cavity or "bubble". This procedure has been around for decades. Risk of complications is
little higher.

                                     MINEXPRESS SHUNT

As the name applies, a small shunt is inserted at the site of Trabeculectomy to allow a controlled
opening. It improves the results of Trabeculectomy. Some times reoperation is required if the
shunt closes.

                                               VALVES

We reserve the use of valves as a last resort in Glaucoma management, if everything else fails.
If successful, they are excellent in pressure control but carry a higher risk of complications.
3535 S. Jefferson, Suite S-4
Saint Louis, MO 63118
Phone   314-771-3000