HOW IS GLAUCOMA DIAGNOSED?
There are a number of tests that can be performed to determine whether someone has glaucoma. These generally involve measuring the IOP, a test to measure peripheral (side) vision and assessments of changes in the optic nerve.
Tonometry measures the inner pressure of the eye providing an IOP reading. Anaesthetic eye drops are used to numb the eye and then the doctor or technician uses a special device (tonometer) to measure the eye’s pressure.
Gonioscopy is a painless eye test using a contact lens that checks to see if the drainage angle of the eye is normal.
This is a simple, quick and painless test to measure the thickness of the cornea. It is important to assess this as it can have a bearing on the accuracy of eye pressure measurements.
4. Visual field testing
Computerised measurements of a patient’s peripheral vision are helpful to diagnose and to monitor glaucoma. During this test, the patient is asked to look straight ahead and indicate when they see a light appear in their peripheral vision. This test helps to draw a “map” of a patient’s vision and any related gaps.
5. Nerve fibre layer measurements
The thickness of the nerve fibre layer can be measured using a non-invasive imaging technique known as Optical Coherence Tomography (OCT). Like visual field testing, this can help in diagnosing glaucoma and also monitor its progression.
6. Optic nerve imaging
Obtaining baseline readings of the optic nerve, and repeating the tests regularly, is important as the doctor can then see if there are any changes over time. Photos and laser scanners are used to provide this information.