Appendix D Screening Instruments

Publication Details

Symptoms Checklist

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Table

Symptoms Checklist.

Amsler Grid Test

This instrument is an effective screening tool for early detection of cytomegalovirus. An Amsler grid can help you monitor your central visual field. It can detect early and subtle visual changes resulting from several macular diseases such as age-related macular degeneration and diabetic macular edema. It is also helpful in tracking changes in vision once they have been discovered. The Amsler grid tests each eye separately. This helps you to recognize visual symptoms that are only in one eye.

The above are examples of two different Amsler grids. Both are useful for monitoring central vision. The grid on the right is a modified Amsler grid (Yannuzzi card) intended to be carried in the wallet or purse for daily self-assessment.

Instructions

Test your vision with sufficient lighting.

Wear your reading glasses or look through the reading portion of your bifocals (if you normally read with spectacles).

Hold the Amsler grid at normal reading distance (about 14 inches).

Cover one eye at a time with the palm of your hand.

Stare at the center dot of the chart at all times.

Do not let your eye drift from the center dot.

Ask yourself the following questions as you check each eye separately:

Are any of the lines crooked or bent?

Are any of the boxes different in size or shape from the others?

Are any of the lines wavy, missing, blurry, or discolored?

Note: If using a rectangular card like the one on the right above (Yannuzzi card), you should check each eye with the card held both vertically and horizontally.

If the answer to any of these questions is “yes” (and this is a new finding for you), you should contact your doctor immediately for an examination. Sometimes these changes may mean that there is leakage in the back of the eye causing swelling of the retina.

Examples of Abnormal Amsler Grids