The Visual Field Grid was designed to allow you to map the scotomas (blind spots) in your central vision. It is easy to do, and it can be used to either monitor your own own progress or to explain your vision to others.
A map of your scotomas can also be obtained from a doctor who is equipped with a computerized perimetry instrument, such as the MP-1-Micro Perimeter developed by Nidek Technologies, Inc. The results look like this:
The MP-1-Micro Perimeter, which has been available since 2003, combines fundus imaging with scotoma mapping. In the results above, 10% of the visual field (the center) was mapped. Green shows the area of good vision, yellow represents diminished vision, and dark red represents no vision. (The larger circle is the area mapped. The bright smaller circle on the left is the optic disc.)
Either the Visual Field Grid or the computerized perimetry results from your doctor can be combined with a digital photograph for showing to family members or for possible publication in the "Through Our Eyes" section of this web site. (For information, see Step 6 of the instructions below.)
To map your visual field, print this page and follow the steps listed. If your print copy is too small, you may enlarge it to any size without affecting the results. Permission is granted to copy and distribute any number of copies of this page, as long as the content remains unchanged. Good luck, and if you need any assistance, please contact Dan Roberts.
|
1. While gazing at the target in the center of the grid, close one eye and move forward until one of the oval spots disappears. (This is your natural blind spot.) 2. While maintaining that distance and keeping your eye closed, make note of those squares in which the numbers are visible. IMPORTANT: This is not an acuity test. You do not have to be able to identify the number peripherally, and it does not matter if it is out of focus. If you are doing this alone, you may need to look away from the center in order to recognize it and write it down. 3. When all numbers have been listed, darken in those squares which are NOT VISIBLE, including the white outlines within the blind area/s. 4. OPTIONAL: Circle the letter above the vertical line on either side of center which is DISTORTED and FURTHEST from the center as you gaze at the target. 5. Using a second copy of the grid, repeat for the other eye. 6. FINAL STEP: If you would like to see your results applied to a digital photograph, send your results in an email, along with your name, type of retinal degeneration, and any other descriptive information (e.g. extent of opaqueness of the blind areas, approximate shade of light or dark in the blind areas, etc.) to Dan Roberts. He will create your photo and email it to you. Please also indicate if you DO NOT want it published on the "Through Our Eyes" web page. FOR THOSE WHO ARE SKILLED WITH PAINT PROGRAMS: If you are reasonably skilled with a paint or draw program, and would like to create your own visual field photo, overlay the finished grid onto a photograph (making sure that the sizes of each image are identical). Then erase all grid squares which are visible, and paint over the squares which are invisible, using the shade of light or dark gray which most closely matches your visual perception. To download a copy of the grid without the accompanying text, right-click anywhere on the image (Macintosh users: "control-click"). |