Number for the minimum angle of resolution (MAR), as part of the NIH Toolbox Sensation Domain Vision Measure Visual Acuity Test

The NIH Toolbox Visual Acuity Test directly measures participants visual acuity, or distance vision. The participant is seated 12.5 feet away from a computer monitor at eye level, and letters (called optotypes) are displayed one at a time on the screen for the participant to identify, using both eyes at the same time, with the participant wearing his/her normal corrective lenses for distance vision (glasses or contact lenses, if worn). As the participant successfully identifies optotypes of a given size, smaller ones appear on the screen, until the computer program ascertains the smallest-size optotype the participant can successfully see. Conversely, the program displays larger optotypes if the participant cannot see the letter size that is first displayed, until a size that he/she can accurately see is found. For participants ages 3 to 7 only the letters H, O, T, and V are used, and children may point to a laminated card showing the letters if they cannot verbalize or cannot recall the letter names. For participants ages 8 and above, the entire set of optotypes is used, following a common protocol used in professional vision testing. This test takes approximately three minutes to administer and is recommended for ages 3-85.

2016-06-03

Copyright 2006-2012 National Institutes of Health and Northwestern University. http://www.nihtoolbox.org/WhatAndWhy/Sensation/Vision/Pages/NIH-Toolbox-Visual-Acuity-Test-.aspx

Once the participant is seated in a chair that is 12.5 feet from the monitor, say: Now we are going to do an activity where you will tell me what letters you see on the screen. You are going to look on this screen (point to monitor) and you will see a letter. Each time, I want you to tell me the letter you saw on the screen. If you are not sure, it is OK to guess. The letters will get smaller and smaller until you cannot really see them. That is ok. We are trying to determine how small they can get before you cannot see them. Are you ready to start? Lets begin. Visual Acuity Test (with glasses or contact lenses if usually worn for distance vision): The examiner should click the START TEST button on the examiners screen. Each time a letter is displayed, say: Tell me, what letter is this? (At the examiners discretion, this can be replaced by: Go ahead after a few letters have been displayed.) It is the examiners job to use the computer to record whether the response was correct or incorrect by clicking either the Yes (correct) or No (incorrect) button. The test will progressively present smaller letters if the participant answers correctly and larger ones if the participant answers incorrectly, until an acuity score is found. The test will automatically end when the computer has calculated the acuity score.

Tue May 08 15:00:30 EDT 2018

NIH Toolbox Dynamic Visual Acuity Test

NIH/CIT/BRICS

Malaika Schwartz

mschwartz@sapient.com

NIH/CIT/BRICS

Olga Vovk

olga.vovk@nih.gov