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Glaucoma

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asrabasi
master optometrest

عدد المساهمات : 70
تاريخ التسجيل : 23/09/2009

Glaucoma

مُساهمة من طرف asrabasi في الخميس 12 أغسطس 2010, 15:47


What is glaucoma?

Glaucoma
is a disease of the optic nerve, which is the part of the eye that
carries the images we see from the eye to the brain. The optic nerve is
made up of many nerve fibers (like an electric cable containing
numerous wires). Glaucoma damages nerve fibers, which can cause blind
spots in our vision and vision loss to develop.

Glaucoma has to do with the pressure inside the eye, or intraocular pressure
(IOP). When the clear liquid called the aqueous humor--which normally
flows in and out of the eye--cannot drain properly, pressure builds up
in the eye. The resulting increase in IOP can damage the optic nerve.

The most common form of glaucoma is primary open-angle glaucoma, where the aqueous fluid
that normally circulates in the front portion of the eye is blocked
from flowing back out of the eye through a tiny drainage system. This
causes the pressure inside your eye to increase, which can damage the
optic nerve and lead to vision loss. Most people who develop primary
open-angle glaucoma notice no symptoms until their vision is impaired.


In angle-closure glaucoma,
the iris (the colored part of the eye) may drop over and completely
close off the drainage angle, abruptly blocking the flow of aqueous
fluid and leading to increased IOP or optic nerve damage. In acute angle-closure
glaucoma there is a sudden increase in IOP due to the buildup of
aqueous fluid. This condition is considered an emergency because optic
nerve damage and vision loss can occur within hours of the problem.
Symptoms can include nausea, vomiting, seeing haloes around light, and
eye pain.

Even people with "normal" IOP can experience vision loss from glaucoma. This condition is called normal tension glaucoma.
In this type of glaucoma, the optic nerve is damaged even though the
IOP is considered normal. Normal tension glaucoma is not well
understood, but we do know that lowering IOP has been shown to slow
progression of this form of glaucoma.

Childhood glaucoma
is rare, and starts in infancy, childhood or adolescence. Like primary
open-angle glaucoma, there are few, if any, symptoms in the early
stage. Blindness can result if it is left untreated. Like most types of
glaucoma, this type of glaucoma may run in families.

Your
ophthalmologist may tell you that you are at risk for glaucoma if you
have one or more risk factors, including elevated IOP, a family history
of glaucoma, a particular ethnic background, advanced age, or certain
optic nerve conditions. Regular examinations with your ophthalmologist
are important if you are at risk for this condition.

    الوقت/التاريخ الآن هو السبت 25 نوفمبر 2017, 04:25