Used to test macular function or to detect a central or paracentral scotoma.

1. Have the patient wear his or her glasses and occlude the left eye while an Amsler grid is held approximately 12 inches in front of the right eye (see Figure A.4.1).

   Figure A.4.1: Amsler grid.

   

2. The patient is asked what is in the center of the page. Failure to see the central dot may indicate a central scotoma.

3. Have the patient fixate on the central dot (or the center of the page if he or she cannot see the dot). Ask if all four corners of the diagram are visible and if any of the boxes are missing. 

4. Again, while staring at the central dot, ask the patient if all of the lines are straight and continuous or if some are distorted and broken.

5. The patient is asked to outline any missing or distorted areas on the grid with a pencil.

6. Repeat the procedure, covering the right eye and testing the left.

NOTE It is very important to monitor the patient’s eye for any movement away from the central dot. A red Amsler grid may define more subtle defects.