Getting regular eye tests is the most effective way of identifying glaucoma in the early stages. Whilst it does have symptoms, these often go unnoticed until the glaucoma has become more advanced. By the time symptoms start to show the damage to the optic nerve is often very serious. In this article I will be discussing some of the most common glaucoma tests and what you should expect.
Gonioscopy
This test uses a special mirrored contact lens to measure the angle where your iris and cornea meet. If the angle is wide and open this could indicate open-angle glaucoma. If it is narrow and closed it could indicate angle-closure glaucoma.
Ophthalmoscopy (Dilated Eye Exam)
This test uses special magnifying lenses to examine your optic nerve for glaucoma damage. Your doctor or eye specialist will look at the colour, health and shape of your optic nerve to assess the potential impact of glaucoma.
Nerve Fiber Analysis
This test measures the thickness of retinal nerve fibers in an attempt to find glaucoma damage. Thinner areas may be a sign of glaucoma damage. Nerve fiber analysis is particularly useful for measuring changes in glaucoma patients. For example, if someone’s retinal nerve fibers become thinner between two exams it shows their glaucoma is getting worse.
Pachymetry
This test uses a pachymeter to measure the thickness of your cornea (the clear surface at the front of your eye). This can then help your doctor or eye specialist fully understand your intraocular pressure levels as the thickness of the cornea does influence them.
Perimetry (Visual Field Test)
This test uses a moving light to measure your complete field of vision. You will be asked to look straight ahead and then tell your doctor or eye specialist when a moving light has entered your peripheral vision. The results of this test will allow your doctor or eye specialist to determine whether your eyesight has been affected by glaucoma.
Tonometry
This test measures the intraocular pressure in your eye. Normal pressure is 12-22 mm Hg (millimetres of mercury – a scale used to measure eye pressure). For most people a reading higher than 20mm Hg can be a sign of glaucoma. However, eye pressure affects everyone differently. Certain individuals may have glaucoma at much lower levels whilst others may not have glaucoma at much higher levels.
Summary
I hope this article has helped you learn a little more about what to expect when you are getting tested for glaucoma. If you have any further questions then ask your doctor or eye specialist. They should be able to answer any questions you may have.