What is glaucoma?
When the pressure inside your eye is damaging the nerve that carries the vision back to your brain, the condition is called glaucoma. The intraocular pressure (IOP) statistical normal range is between 10 and 21 mm Hg. Some patients may have pressure higher than 21 mm Hg but do not develop glaucoma. Other patients may develop glaucoma with a pressure less than 21 mm Hg.
What are the symptoms of glaucoma?
Most patients with glaucoma have a type of glaucoma called open-angle glaucoma. At an early stage, the open angle glaucoma has no symptoms. Unfortunately, when you start noticing symptoms, you will have already lost a good deal of the nerve fibres that carry vision back to your brain. It is better for glaucoma to be detected early and treated appropriately to prevent damage.
Is glaucoma painful?
Most open-angle glaucomas are not painful. There is another type of glaucoma called angle-closure glaucoma that can cause significant eye pain and blurred vision and needs urgent treatment in the form of eye drops, laser (PI) and sometimes tablets.
How do I find out if I have glaucoma?
By an eye examination which will include measuring the pressure inside of your eyes (this is different from blood pressure), as well as examining the inside of your eyes. You may also require some additional tests.
What kind of tests?
Testing your peripheral vision (Field test), measuring the thickness of the nerve layer at the back of your eye by a special laser camera (OCT test) and measuring the thickness of the cornea (the hour glass of the eye), called pachymetry.
Visual Field Test – With glaucoma, the peripheral field of vision is usually the first to be affected. Periodic visual fields are performed to detect new field defects, or determine a worsening or deepening of established field loss over time.
OCT test – Ocular coherence tomography
OCT provides a contour map of the optic nerve-head and also measured the retinal nerve fibre layer (RNFL) thickness. It provides an objective, repeatable measurement which can give an earlier more accurate diagnosis of glaucoma. RNFL measurements are compared to the normal population, as well as those taken at previous visits. This allows the detection of RNFL thinning which is indicative of disease progression.
Central corneal thickness (CCT) is measured in order to determine the true IOP measurements. Evidence suggests that thicker than average corneas result in an overestimation of true eye pressure, while thinner corneas result in an underestimation of true eye pressure.
If I have glaucoma what is the treatment?
Most patients will respond well to either eye drops and/or laser treatment (SLT) to lower the pressure in the eye. Very few glaucoma patients need surgery.
What does the laser involve?
Selective laser trabeculoplasty (SLT) use a laser beam of very short duration to help the fluid inside he eye to exit through the natural tiny holes at the front part of the eye. Local anaesthetic eye drops are instilled to numb your eye. The doctor applies a lens to your eye. The laser is mostly painless. The procedure only takes a few minutes and is performed at Hawthorn Eye Clinic.
What happens in glaucoma surgery?
You will receive an injection in the vein in the arm, to make you sleepy. The anaesthetist will apply local anaesthetic to make your eye numb so you will not feel any pain. The surgery entails making a pathway for the fluid inside the eye to drain out of the eye in a controlled manner to allow the pressure inside you eye to lower. The aim of this procedure is to reduce the eye pressure and preserve vision.
Is there any risk with the surgery?
The success rate is good. But in some patients the surgery may not work, or it may lower the pressure inside the eye too much. There is a small risk of bleeding and infection. When complications happen, they are usually amenable to treatment. The risk of losing the eye or losing vision is very low. The risk of the anaesthetic is also low.
If I have glaucoma will I become blind?
By keeping your glaucoma under control the risk of blindness from glaucoma is very unlikely.
When do I need to get my eyes checked for glaucoma?
Anyone above the age of forty should be checked for glaucoma.
How often do I need to be checked for glaucoma?
A. If your eye examination is completely normal, then every 2 to 3 years. If a close member of your family has glaucoma or the eye examination revealed some suspicious findings, you will need to be seen more often.