Sometimes
referred to as the trabecular meshwork or, Schlemm’s canal.
5-FU - A medication
that stops the healing process. Sometimes used around the
new drainage hole created during surgery (the bleb) to stop
it from healing or scarring over.
Glaucoma Suspect
- A person may be considered a glaucoma suspect
on the basis of high intraocular pressure, a suspicious
appearance of the optic disc or visual field, a family history
of glaucoma, or narrow angles between the iris and cornea.
Gonioscopy -
In this test, a contact lens that contains a mirror is gently
placed on the eye. The mirror lets the doctor look sideways
into the eye to check whether the angle where the iris meets
the cornea is open or closed. This helps the doctor decide
whether open-angle or angle-closure glaucoma is present.
Intraocular
Pressure (IOP) - The internal pressure of the eye.
Normal intraocular pressure usually ranges from 10-22 mm
Hg, although people with relatively low pressures can still
have glaucoma (see normal tension glaucoma.)
Iris - The colored
part of the eye that can expand or contract to allow just
the right amount of light to enter the eye.
Laser Surgery
- A type of surgery in which a tiny, powerful beam of
light is used to solve problems in the eye. There are three
common forms of laser surgery for glaucoma:
-
Laser Peripheral Iridotomy - Creates
a new drainage hole in the iris, allowing the iris to
fall away from the outflow channel so fluid can drain
out of the eye.
-
Laser Trabeculoplasty - In this procedure,
the laser is aimed toward the normal drainage channels
of the eye, in an attempt to open those channels so
fluid can leave the eye more efficiently.
-
Laser Cyclophotocoagulation - This laser
procedure is usually used in people who have severe
glaucoma and are not responsive to standard glaucoma
surgery. Laser energy is used to partially
destroy the tissues that make the fluid within the eye.
Lens - Located behind
the iris, helps light focus onto the retina.
Microsurgery -
Surgery performed with a microscope in which and instrument
is used to make a tiny, new opening in the sclera so that
intraocular fluid can drain out of the inside of the eye.
Mm Hg - An abbreviation
for “millimeters of mercury,” which is a scale for recording
intraocular pressure.
Normal
Tension Glaucoma - A rare form of glaucoma in which
intraocular pressure stays within the normal range (10-22
mm Hg), but damage still occurs to the optic nerve and visual
fields.
Ophthalmoscopy
- A test designed to examine the inside of the eye,
especially the optic nerve. An instrument with a small light
on the end is held up to the inside of the eye in a darkened
room. This instrument lights up and magnifies the eye, and
lets the doctor look at the shape and color of the optic
nerve.
Optic Nerve -
The nerve in the back of the eye that carries visual images
to the brain.
Perimetry -
(Also known as the visual field test.) A test that produces
a map of the complete field of vision, designed to determine
whether there is damage to any area of vision.
Peripheral Vision
- The top, sides, and bottom areas of vision, which
are usually the first areas of vision affected by glaucoma.
Pupil - The
opening that regulates how much light enters the inner part
of the eye.
Retina -
The part of the eye that carries light and images to
the brain through the optic nerve.
Sclera -
The tough, white, protective, outer coat of the eye.
Tonometry
- The use of a device to measure the pressure
within the eye. There are three types of tonometry:
-
Air Puff - This is the only type of
tonometry that does not touch the surface of the eye.
The patient sits upright at the instrument, and a
warm puff of air is directed at the eye.
-
Applanation - The patient’s eye is
first treated with numbing drops and a stain called
fluorescein. The tonometer is then placed gently on
the cornea, and a very small amount of pressure is
applied to the cornea. The patient may sit in front
of the tonometer or a hand-held tonometer may be used.
-
Schiotz - This type of tonometer was
formerly used in the operating room or
with people who are unable to sit upright (such as
infants or small children). The patient is lying down
or sitting back. After use of a numbing drop, the
tonometer is placed gently on the front part of the
eye. This type of tonometry is rarely used today.
Trabecular
Meshwork - The formal name of the mesh-like drainage
canals all around the iris.
