1. Use Symptoms as a Guide
Some symptoms, such as blurred vision, can indicate a constellation of potential eye disorders. For instance, blurry vision might indicate astigmatism, farsightedness, nearsightedness, cataracts or other less common and potentially more dangerous disorders. However, other symptoms may be much easier to trace to a cause. For instance, if colors look to be more yellow than normal, your eyes don't move together and you experience triple images in either your right or your left eye, it is likely that you have a cataract. Keep a log of symptoms as they occur, including how and when they present, their duration and their intensity.
2. Tests of Visual Acuity
Your ophthalmologist can give you several different tests to determine the resolving power of your eyes. Visual acuity exams can test for nearsightedness, farsightedness and astigmatism and your eye doctor may prescribe contact lenses or glasses depending on the results of your exam. A typical visual acuity test involves reading letters off a chart at a distance. Just because you don't score a 20/20 on such a test, however, doesn't indicate that you have a visual problem. In fact, there's a significant amount of natural variation in visual acuity among healthy patients; indeed, studies suggest that there may even be substantial variation in acuity even within a single patient from day to day.
3. Tests for Color Vision
Improperly adjusted, fading or erratic color vision may indicate a number of conditions, from simple inherited color blindness to diseases of the optic nerve, such as optic neuritis, to more whole body problems and diseases, like multiple sclerosis.
4. Refraction Tests and Visual Field Exams
These tests are usually given in conjunction with visual acuity exams to test for nearsightedness, farsightedness and other issues relating to the peripheral vision. They can be used to fine-tune the diagnosis of the visual problem.
