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Glaucoma Diagnosis

As a general figure it is estimated that between 3-4% of the population over 40 have glaucoma. The alarming thing is that it is estimated that 50% of this figure don't know they have it.

Getting your eyes examined is vital to reducing sight loss by glaucoma. Without such an examination it is likely that the first symptom you will have is peripheral sight loss and that loss is likely to be permanent.


  • A tonometer is used as part of a regular eye exam to measure your intraocular pressure or IOP. Your eye typically is numbed with eye drops, and a small probe gently rests against your eye's surface. Other tonometers direct a puff of air onto your eye's surface and do not require direct eye contact. Normally, IOP should be below 21 mmHg (millimeters of mercury) — a unit of measurement based on how much force is exerted within a certain defined area. If your IOP is higher than 30 mmHg, your risk of glaucoma damage is 40 times greater than someone with an IOP of 15 mmHG or lower.

  • Visual field testing is another way to monitor whether blind spots are developing in your range of vision, resulting from glaucoma damage to the optic nerve. Visual Field Testing involves staring straight ahead into a machine and clicking a button when you notice a blinking light in your peripheral vision. The visual field test may be repeated at regular intervals so your eye-doctor can determine the extent of vision loss.

  • Close examination of the Optic Disk for damage.


All the above methods require a trip to the eye doctor. However, recently a new method known as the “Welsh Test” developed by Dr Welsh is an effective method for people to self-test themselves for Glaucoma. The importance of this test is that it can catch Glaucoma at a much earlier stage and can be done at home by anyone who can follow a set of instructions. Full details of this test are provided in the Glaucoma action plan. Use this test to reassure yourself about your visual health but if you are in a risk group, do not use it as a replacement for a full eye-checkup.

If glaucoma is diagnosed there is an array of sophisticated equipment for imaging, monitoring and screening the state of the optic nerve and other eye structures. These scans can be used to see what is going on and to monitor any glaucoma damage.