Glaucoma is a group of eye diseases causing optic nerve damage. The optic nerve
carries images from the retina, which is the specialized light sensing tissue,
to the brain so we can see. In glaucoma, eye pressure plays a role in damaging
the delicate nerve fibers of the optic nerve. When a significant number of
nerve fibers are damaged, blind spots develop in the field of vision. Once
nerve damage and visual loss occur, it is permanent. Most people don't notice
these blind areas until much of the optic nerve damage has already occurred. If
the entire nerve is destroyed, blindness results. Glaucoma is a leading cause
of blindness in the world, especially in older people. Early detection and
treatment by your ophthalmologist are the keys to preventing optic nerve damage
and vision loss from glaucoma.
The exact causes of optic nerve damage from glaucoma is not fully understood,
but involves mechanical compression and/or decreased blood flow of the optic
nerve. Although high eye pressure sometimes leads to glaucoma, many people can
also develop glaucoma with "normal" eye pressure.
is the most common form of glaucoma. The
"open" drainage angle of the eye can become blocked leading to
gradual increased eye pressure. If this increased pressure results in optic
nerve damage, it is known as chronic open-angle glaucoma. The optic nerve
damage and vision loss usually occurs so gradually and painlessly that you are
not aware of trouble until the optic nerve is already badly damaged.
when the drainage angle of the eye narrows and becomes completely blocked. In
the eye, the iris may close off the drainage angle and cause a dangerously high
eye pressure. When the drainage angle of the eye suddenly becomes completely
blocked, pressure builds up rapidly, and this is called acute angle-closure
glaucoma. The symptoms include severe eye pain, blurred vision, headache,
rainbow haloes around lights, nausea and vomiting. Unless an ophthalmologist
treats acute angle-closure glaucoma quickly, blindness can result. When the
drainage angle of the eye gradually becomes completely blocked, pressure builds
up gradually, and this is called chronic angle-closure glaucoma. This form of
glaucoma occurs more frequently in people of African and Asian ancestry, and in
certain eye conditions.
is a rare genetic disorder (estimated to occur in one in 50,000 newborns) that
causes abnormalities of bone, joints, fingernails, kidneys, and glaucoma.
Not all types of glaucoma are characterized by eye pressures. In normal-tension
or low-tension glaucoma, the optic nerve suffers damage with the resulting
visual field loss even though normal eye pressures are maintained. Eyes
afflicted with this condition are far more susceptible to optic nerve damage
with any increase in the intraocular pressure compared to other eyes.
common form of open-angle glaucoma that results when there is a buildup of
abnormal, whiteish material on the lensand drainage angle of the eye. This
material and pigment from the back of the iris can clog the drainage system of
the eye, causing increased eye pressure. This form of glaucoma responds well to
condition that typically affects young, nearsighted, Caucasian males. This
condition is characterized by the iris bowing backwards, and coming into
contact with the support structures that hold the lens in place. This position
disrupts the cells lining the back surface of the iris containing pigment, and
results in a release of pigment particles into the drainage system of the eye.
This pigment can clog the drain and can lead to an increase in eye pressure.
This form of glaucoma responds well to laser treatment.
Other types of glaucoma may be caused by
injuries to the eye, tumors, and other eye diseases. A rare type of glaucoma
can even be present in children at birth.