| A nerve fiber layer defect from glaucoma shown in a special photograph and by optical coherence tomography|
Each year at the Dean McGee Eye Institute we treat nearly 5,000 patients who have moderate to very advanced glaucoma. Many of these patients could have benefited from much earlier diagnosis or more careful and precise monitoring of their risk factors. Other patients who already are known to have glaucoma can benefit from more accurate assessment of their risk of progression of the disease over time with more advanced assessment in order to prevent further vision loss over time. To achieve a full and accurate assessment, experienced ophthalmologists, optometrists, and technical support staff, perform different parts of a comprehensive glaucoma screening that consists of several different areas of testing. In its early stages glaucoma is very difficult to diagnose and several different approaches need to be used to accurately assess whether a patient has glaucoma or more accurately assess their risk of developing the disease. All tests in glaucoma assessment are painless, non-invasive, and safe.
Measurement of intraocular eye pressure (IOP). Elevated IOP is considered a major risk factor for the development of glaucoma. Studies have shown that optic nerve damage becomes more likely as the IOP increases. Measurement of the corneal thickness also provides valuable information about the accuracy of the pressure measurement as well as additional information about the risk of glaucoma. Measuring intraocular pressure at different times of the day may be important in some cases.
Assessment of the optic nerve. A non-invasive slit lamp biomicroscope is used to determine whether or not there are changes in the optic nerve consistent with the diagnosis of glaucoma. Stereo photographic or advanced imaging techniques of the nerve fiber layer of the optic nerve may also be used such as Optical Coherence Tomography. These instruments may show damage from glaucoma at a much earlier stage then can be detected by other methods and may also show progression before other methods can.
Evaluation of a patient's peripheral visual field. Glaucomatous damage produces characteristic defects in the visual field or peripheral vision, but with standard visual filed testing glaucoma damage may not become evident until significant optic nerve damage occurs. At the Dean McGee Eye Institute we employ several different advanced techniques, including Short Wavelength Automated Perimetry, which sometimes can detect glaucomatous visual field damage far earlier than more standard tests.
Depending on the exact situation, the diagnostic tests performed during a glaucoma evaluation will be individualized for each patient based on their exact needs. Usually one of the glaucoma specialists will carefully go over the results of all these tests integrating them into a complete assessment for each patient to arrive at an appropriate plan of treatment.