This is a more accurate test for your eye pressure. You will have a yellow dye put in your eye and under the microscope, a probe will touch your eyes to take a measure of your eye pressure. This test is usually done if the 'air puff' eye pressure test reads high or a more accurate reading of your eye pressure is required. Eye pressure measurement is very important in assessing the risk of glaucoma. If necessary by NHS protocol this test can be FREE on NHS.