What is glaucoma?
There are many different varieties of glaucoma, the most common types being open- and closed- angle. The angle of the eye is a structure where the cornea or clear part of the eye meets the iris (colored part of the eye.) The trabecular meshwork resides in the angle, acting as a drain for the fluid produced behind the iris in the ciliary body.
- Open-angle glaucoma is when there is no obstruction of the fluid into the angle of the eye, although, fluid is inhibited from leaving the eye through a faulty drainage structure leading to chronically, elevated pressure in the eye
- Closed-angle glaucoma is when the angle structures are obstructed by a forwardly displaced iris, possibly leading to acute elevations of the pressure of the eye, pain, and loss of vision.
What are the symptoms of glaucoma?
Most patients experience no symptoms of glaucoma making it very difficult to know if they have the disease at all. In the later stages of glaucoma patients may notice:
- Decrease in peripheral or central vision,
- Eye pain
- Halos around lights
How is glaucoma diagnosed?
Glaucoma is usually discovered on a routine eye exam. Patients are urged to undergo an eye exam particularly if any family members have been affected by the disease. There are several different tests utilized in detecting glaucoma including:
- Visual field - a test for the peripheral vision
- Gonioscopy - a specialized contact lens used to visualize the angle of the eye
- Tonometry - an instrument used to determine the pressure within the eye
- Dilated examination - allows visualization of the optic nerve through a large pupil to determine irregularity of the shape and contour of the optic nerve which physically changes as glaucoma progresses
How do you treat glaucoma?
When glaucoma is diagnosed it may be initially treated with medications or with laser procedures depending on what your surgeon decides. The types of laser include:
- Selective laser trabeculoplasty – so called because the laser energy is selectively absorbed by pigmented tissue causing inflammation and increased drainage through the trabecular meshwork reducing the intraocular pressure up to 30%. The affects are seen within 1-3 months and may last from 1-5 years. Repeated treatments may be performed if the effects wear off.
- Laser peripheral iridotomy - is used in cases where there are narrow angles. A small hole is placed through the peripheral iris or colored part of the eye. The hole allows for fluid produced behind the iris in the ciliary body to be detoured instead of flowing around the pupil. The iris is then allowed to move backward from the cornea, opening the angle of the eye.
These laser procedures are usually performed in under 5 minutes in an outpatient setting. Patients have reported a pressure-like or stinging sensation during the procedure, but overall they are considered painless. Following the procedure patients may experience blurring of their vision and irritation.
If you have glaucoma and visually-impairing cataracts your surgeon may decide to utilize techniques to lower the intraocular pressure at the time of cataract surgery. These techniques are known as Minimally Invasive Glaucoma Surgeries. For more advanced cases of glaucoma may require invasive forms of surgery such as a trabeculectomy or glaucoma tube shunt. Talk to your doctor regarding your options.