To diagnose glaucoma, we will perform a range of tests that are designed to measure the quality of your vision and detect any potential damage to the optic nerve. These tests include a traditional eye chart text, the visual acuity evaluation allows us to examine your distance vision. Visual Field Test allows us to examine your field of vision, including much of your peripheral vision. Although initially this may be a difficult test for patients to take, and there is a small learning curve, most patients will be able to participate in this type of testing. This is a very important test for patients with glaucoma and must be repeated over time. The pattern of vision loss helps us to determine if a patient has glaucoma. It also allows us to follow patients over time, to determine whether their vision loss has been halted by their current treatment regimen. More aggressive treatment may be needed in those patients whose visual field test shows continued vision loss over time.
By dilating, or widening, the pupil, we can examine the retina and optic nerves directly, through the use of special magnifying lenses. This allows us to look for optic nerve damage or other conditions which may affect vision. Patients with glaucoma often have a particular appearance of their optic nerves, which is best appreciated on dilated eye exam. Patients with “suspicious optic nerves” may be asked to undergo more specific, thorough glaucoma testing to help determine whether they actually have glaucoma or are “glaucoma suspects” and need to be monitored over time. Glaucoma is caused by pressure on the optic nerve. Through the use of an instrument called a tonometer, we can measure pressure inside the eye and determine whether it's abnormally high. High pressure can indicate the onset of glaucoma, or the potential for glaucoma development. Most glaucoma treatments are focused on lowering the eye pressure, therefore it is important to determine what the actual pressure is in the eye. Once we know the eye pressure, we can determine what treatments to use in order to lower the pressure, as well as by how much we need to lower the pressure. Since all patients have different pressure in their eyes before treatment, every patient needs to have their pressure lowered to a different level during treatment. Glaucoma treatment is very individualized. We also measure the thickness of your cornea. After numbing the eye with eye drops, we employ an instrument that emits an ultrasonic wave to measure corneal thickness. We then use this information, with the tonometry reading, to calculate the eye pressure. Optical Coherence Tomography, this technique provides a non-invasive means of measuring the thickness of the retinal nerve fiber layer (RNFL) by directing light at the tissue and measuring its return. The benefits of this technique are many: near-microscopic resolution of sub-surface features, non-invasive, instant results, no preparation required, and no ionizing radiation exposure. With this data, we can compare the thickness of your retinal nerve fiber layer to that of a normative database. This test allows us to follow changes in your optic nerve health over time. We use this information in conjunction with the appearance of your optic nerves and visual field tests to determine if there are any changes in your eye health or vision occurring over time. Glaucoma treatment is aimed at preventing these changes over time, thus preserving as much vision as possible. Gonioscopy involves the use of a specialized lens, known as a goniolens, with a mirror to examine the iridiocorneal angle where the fluid drains from the eye. The angle is at the edge of the iris at the point where it meets the cornea. Because of the presence of the cornea, and total internal reflection, it is impossible to examine this drainage angle directly, necessitating the use of a mirrored goniolens. There are several different methods of gonioscopy, each based on the different lens utilized for examination. The purpose of gonioscopy is to visualize the drainage angle structures, assess how open the drain is, and to determine if there is any excess pigment or scarring present that may impede acqueous humour outflow and thus increase eye pressure.