Glaucoma is a progressive eye disease that damages the optic nerve. Because the optic nerve transmits information from your eye to your brain, glaucoma can result in a gradual, irreversible loss of vision and may eventually lead to blindness. Although there are different types of glaucoma, high intraocular pressure (IOP), also referred to as high eye pressure, is often present and is one of several risk factors for glaucoma. However, many patients with glaucoma do not have elevated IOP which is why a comprehensive eye exam, including an examination of the optic nerve, is important for early diagnosis.
Glaucoma is known as “the silent thief of sight.” Most people have no symptoms until permanent vision loss has already occurred. Regular comprehensive eye exams are the key in the diagnosis of glaucoma.
A comprehensive exam will always include tonometry to measure the IOP in the eyes and ophthalmoscopy to inspect the optic nerve. If either the IOP or the optic nerve appears suspicious for glaucoma, then further testing will be ordered by your doctor.
Additional testing may include gonioscopy to look at the drainage system of the eye, pachymetry to measure corneal thickness, an OCT to measure the tissue of the optic nerve and a visual field test. The visual field test is critical in determining if vision loss may have already occurred.
OPEN ANGLE GLAUCOMA
The most common type of glaucoma is open-angle glaucoma. Approximately 90% of all glaucoma cases are considered open-angle. Usually, it begins with elevated IOP. Although not fully understood, the drainage system becomes less efficient over time, which causes a gradual increase of fluid in the eye and therefore an increase in IOP. This increase can cause damage to the optic nerve.
NARROW ANGLE OR ANGLE CLOSURE GLAUCOMA
This type of glaucoma is directly related to the anatomical shape of the eyeball. The fluid produced inside the eye flows from behind the iris to the drainage channel that runs in a band just inside the front of the eye between the cornea and the iris. If the space between the cornea and the iris is narrow or shallower than normal, the iris can block the drainage channel. This can cause a very sudden, increase in IOP which can lead to severe pain in or around the eye, headache, very blurred or cloudy vision, nausea and/or vomiting. This is an acute angle closure attack of glaucoma and is a medical emergency.
This is caused by a severe blow to the eye or eye socket. Injury to the eye at any age can cause damage to the drainage system of the eye. If you have ever had an injury to the eye, it is important to report this to your eye care professional.
Once a patient is diagnosed with glaucoma, there are several treatment options available. Generally, the first option is prescription eye drops to help lower and/or control the IOP. This may require one or more type of drops.
A second option is laser surgery treatment. This is an in-office procedure that takes just a few minutes. It is usually done in conjunction with prescription eye drops.
In some cases, drops and laser treatment may not be effective enough in controlling the IOP. This is when the doctor may recommend surgery as the next step for glaucoma treatment.
The surgery can also include insertion of a micro-stent or a procedure to widen the drainage system of the eye. The goal of either procedure is to lower the IOP.
Filtration surgery is another type of procedure that helps lower the IOP. One type involves implanting an aqueous shunt into the eye to assist in draining fluid out of the eye. Trabeculectomy is another surgery that makes an opening in the eye to drain fluid.