Glaucoma is one of the more interesting diseases that we deal with as eye doctors. This is because of the structures that the disease attacks, the nature in which they are impacted by the disease and the impact that the disease has on our patients’ visual functioning.
Structures in the front and back portions of the eye are involved in Glaucoma. From the cornea to the iris and lens and what is called the “anterior chamber angle” in the front of the eye to the retinal ganglion cells and optic nerve in the back of the eye, many different things have to be evaluated when we are examining our patients who have Glaucoma or who are suspected of having Glaucoma. Careful and repeated evaluation of these structures need to be performed if we are to diagnose Glaucoma in its earliest stages, which is desirable as we can then take steps to prevent permanent vision loss. Because the tissues that were are studying are very detailed and fine, deciding if a change has truly occurred can be difficult. Multiple measurements are often required to determine if a patient truly has Glaucoma or not.
We also measure the function of the optic nerve and the visual system when evaluating both patients suspected of having Glaucoma and actual Glaucoma patients. The tests that we use to do this are subjective in nature, meaning that the patient is actively involved in the creation and capture of the data. This introduces a fairly involved and complicated factor, determining if a change in the patients visual function is due to progression of the disease or due to variations in the testing such as patient inattention, distraction, fatigue or a whole host of other potential issues. For this reason, multiple assessments of the patient’s visual function (via a Visual Field test) are required to confirm the presence of Glaucoma or the progression of the disease.
Current research is pointing out a need for more frequent visual field testing in order to determine the presence of the disease or the progression of the disease. Fortunately, in the vast majority of patients, Glaucoma is not a fast progressing disease. This means that we have time to repeat our testing to insure that any diagnoses we make or changes to treatment plans are due to actual disease or progression of disease.