A chart used to detect a type of age-related change in central vision known as macular degeneration. The chart looks like a piece of paper with dark lines forming a square grid around a dot in the center. The grid is held at a comfortable reading distance with one eye covered while the person focuses on the center dot; the test is then repeated with the other eye covered. Blurring of the grid or distortion of its lines into wavy, fuzzy, or missing areas of vision can indicate damage to the macula, most commonly from macular degeneration.
A grid of lines used in testing for macular degeneration. The grid is observed with each eye separately.