| Glaucoma is a group of eye diseases
that are characterized by intraocular pressure levels that
damage the optic nerve and nerve fibers that form parts of
the retina in the back of the eye. The optic nerve links the
light-perceiving tissues of the eye with the parts of the
brain that process visual information. Glaucoma is a common
cause of preventable vision loss and can be treated by prescription
drugs, laser therapies, and surgery. People with glaucoma
often have no symptoms until they begin to experience loss
of part of their peripheral vision. It is important to note
that visual loss from glaucoma is permanent and irreversible
in most cases, hence the need for early diagnosis and treatment.
Visual field loss is one of the three
main signs of glaucoma and is the result of damage to the
optic nerve. Once damaged, visual losses are not reversible.
(Photo courtesy National Eye Institute)
The ophthalmologist making a diagnosis
of glaucoma will look for three conditions:
- Higher intraocular pressures are associated
with a higher risk for developing the disease. In addition,
it is known that the chances of maintaining vision and side
or peripheral vision are related to decreasing pressure
within the eye.
- Loss of tissue or cupping in the center of
the optic nerve head or disc at the back of the eye, which
suggests optic nerve damage or reduced function.
- Visual field loss or defect of a glaucomatous
type (typically a reduction of peripheral vision, or an
increase in the number or size of blind spots) (see photos
above).
Some or all these signs may be present if a
person has glaucoma. The condition of the optic nerve head
and raised intraocular pressure are only detectable during
an eye examination by an ophthalmic professional. |
