What is Glaucoma?
Glaucoma is a disease that damages the optic nerve of the eye. The optic nerve sends signals from the retina to the brain and these signals are interpreted as the images you see.
In the healthy eye, a clear fluid called aqueous humor circulates inside the front portion of your eye. This will maintain a constant healthy eye pressure. The eye continually produces a small amount of aqueous humor while an equal amount of this fluid flows out of your eye, we are not talking about tears. This fluid is inside the eye ball. If you have glaucoma, the aqueous humor does not flow out of the eye as it should, thus creating pressure build up in the eye. Over time this pressure causes damage to the optic nerve fibers.
Different types of Glaucoma
There are several types of glaucoma. The main types are:
- Open-angle glaucoma
- Normal-tension glaucoma (or normal pressure glaucoma)
- Closed-angle glaucoma (or Narrow-angle glaucoma or Angle-closure glaucoma)
One of the problems with glaucoma, especially open-angle glaucoma, is that there are typically no symptoms until late in the disease. Many people who have the disease do not know they have it. This is why it is important, especially as you get older, to have regular medical eye exams by an eye specialist.
The assessment includes:
Tonometry: Measuring the pressure in the eye.
Ophthalmoscopy + OCT: an assessment of the optic nerve.
Visual Field: Test of peripheral vision.
Pachymetry: Measuring the thickness of the cornea, the clear window at the front of the eye.
Medicated eye drops is the most common way to treat glaucoma. These medicated drops lower the eye pressure in one of two ways:
- Slowing down the production of aqueous humor
- Improving the out flow through the drainage angle.
In some cases, patients with glaucoma can undergo surgery.
Surgery can be done with laser or open surgery. Glaucoma surgery would then improve the flow of fluid out of the eye, resulting in lower eye pressure.
Laser surgery is done in the clinic as an outpatient procedure. It can take about 10 minutes to treat one eye. It is done with local aneasthesia and is not painful.
The laser creates changes on the trabecular meshwork thereby, improving the outflow of aqueous. The effect is seen within days and often drops may not be required after the treatment, or less drops would be required
Open surgery is done in theatre, and is typically done under general anaesthesia. In this form of treatment, a new channel is created to drain the aqueous away.
Surgery is typically reserved for patients where pressure control cannot be achieved with drops.