If you have glaucoma, you probably don’t know unless an eye doctor has diagnosed it. In its early stages it gives no symptoms. However, it does start damaging your optic nerve right from the beginning, before reducing your peripheral vision, which is why it’s so important to diagnose it early.
Tonometry measures the pressure inside your eyes. Glaucoma is usually associated with higher-than-average intraocular pressure (IOP); although in some cases a person can have glaucoma along with normal IOP. For a tonometry test, you sit at a slit-lamp. You rest your chin and forehead on the supports and Thomas moves the tonometer forward so that it briefly touches your cornea after anaesthetic drops have been applied to your eye. That’s all there is and it takes just seconds.
A pachymeter measures how thick your corneas are – your Central Corneal Thickness (CCT). It’s helpful to know your CCT because if your corneas are thicker or thinner than average, that can affect measurements of your IOP. You need only do this test once, since corneal thickness remains steady.
Visual Field Test
Your visual field is everything you can see at any given time – both what you are looking at directly and what you see around the edges. This test takes about half an hour to measure how complete your visual field is. It essentially records the quantity and quality of what you see. If you have glaucoma, a Visual Field Test should be taken at least twice a year, as it will help Thomas assess your treatment’s effectiveness.
Finding Optic Nerve Damage
Thomas will also examine your eyes through the slit lamp ophthalmoscope. It allows him to see the back of your eye and study the optic nerve. By the colour and appearance of the nerve, he can tell whether any damage has been done. There are many features of a damaged optic nerve that are specific to glaucoma such as the phenomenon called cupping.