Glaucoma is a group
of eye diseases in which the optic nerve is damaged leading to irreversible
loss of vision.
In most cases,
this damage is due to an increased pressure within the eye.
The eye produces a fluid called aqueous humor
which is secreted by the ciliary body into the posterior chamber –
a space between the
iris and the lens.
It then flows through the pupil
into the anterior chamber between the iris and the cornea.
From here, it drainsthrough a sponge-like structure located at
the base of the iris called the trabecular meshwork and leaves the eye.
In a healthy eye,
the rate of secretion balances the rateof drainage.
In people with glaucoma, the drainage canal is partially or completely blocked.
Fluid builds up in the chambers and this increases pressure within the eye.
The pressure drives the lens back and presses
on the vitreous body which in turn compresses and damages
the blood vessels and nerve fibers running at the back of the eye.
These damaged nerve
fibers result in patches of vision loss,
and if left untreated, may lead to total blindness.
There are two main types of glaucoma: open-angleand angle-closure.
Open-angle glaucoma, or chronic glaucoma,
is caused by partial blockage of the drainage canal.
The angle between the cornea and theiris is”open”, meaning the entrance to the
drain is clear, but the flow of aqueous humor is somewhat slow.
The pressure builds up gradually
in the eye over a long period of time.
Symptomsappear gradually, starting from peripheral
vision loss, and may go on unnoticed until the central vision is affected.
of glaucoma can be stopped with medical treatments,
but part of vision that is already lost can
not be restored.
This is why it’s very
important to detect signs of glaucoma early with regular
eye exams. Angle-closure glaucoma, or acute glaucoma,
is caused by a sudden and complete blockage of aqueous humor drainage.
The pressure within
the eye rises rapidly and may lead to total vision loss quickly.
Certain anatomical features
of the eye such as narrow drainage angle,
shallow anterior chamber, thin and droopy iris,
make it easier to develop acute glaucoma. Typically,
this happens when the pupil is
dilated and the lens is stuck to the back of the iris.
This prevents the aqueous humor
from flowing through the pupil into the anteriorchamber.
Accumulation of fluid in the posterior
chamber presses on the iris causing
it to bulge outward and block the drainage angle completely.
Acute angle-closure glaucoma isa medical emergency and requires immediate