A lighted instrument called an ophthalmoscope is used to examine the retina. With this instrument the ophthalmologist can see areas of the retina that might be affected. In addition, some special tests may be administered. The Amsler Grid test, in which a patient looks at a page similar to graph paper, is used to detect blind spots or distortion of central vision. A color vision test will indicate damage to the macula if the patient cannot detect symbols or letters camouflaged in color patterns.