The start of any eye care begins with a simple Revision Supplement Reviews vision test. People have been poking fun at eye charts for many years but this simple test can help reveal some serious and not so serious problems. When conducting an eye test, the optometrist will place an object over the patient's one eye while testing the vision of the other. The patient will read the letters off the chart. On each line of the chart the letters are a little smaller than on the line above. The reason each eye is tested separately is because your eyes actually work independently of each other and one eye can be weaker than the other, especially if under the stress of much reading, or these days computer work.