This app is a test to measure reaction times in vision. The user starts the test by pressing the tab 'Start Trial'. After this tab is pressed, a visual stimulus is presented. The visual stimulus is made of black or white squares embedded in a noisy background. The user has to count as fast as possible the number of squares and press a tab with the correct number, which can be 1, 2 or 3. Once a tab is pressed, another stimulus appears and this sequence is repeated until the user stops the test. A minimum number of trials (200) is required to obtain reliable data, however, the user can finish the test at any time by pressing 'End Trial'. When 'End Trial' is pressed, the user can see the average reaction time (e.g. 'Mean White RT: 0.739 seconds', 'Mean Black RT: 0.723 seconds') and the accuracy of the visual performance (e.g. 'White percent of correct answers: 88.7%', 'Black percent of correct answers: 89.1%').

When 200 trials are completed, there is an option to mail the data to our laboratory and to the user's email address. The data will be mailed in the form of a data sheet that contains information about the data collected (e.g. reaction times and correct responses for individual trials) and information about the variables selected for the test. The variables can be set before the test begins (e.g. size of noise, size of targets, ratio of black and white area, number of trials). After the data is mailed, the app provides a score of performance based on the speed and accuracy of the count. The score ranges from 0 to 100 (100 being best performance).

This visual test was inspired by published work from the laboratories of Drs. Jose Manuel Alonso and Qasim Zaidi (Komban et al., 2011, 2014; Wool et al, 2015). The app was written by Vandad Davoodnia as part of a collaboration between the laboratories of Dr. Reza Lashgari and Dr. Jose Manuel Alonso. The purpose of this app is to provide eye doctors with a tool for vision research. Collecting data with this app could also help to improve current visual tests and/or develop new tests that can be used to monitor the progression of a visual disease.

1) Komban, S. J., J. M. Alonso and Q. Zaidi (2011). Darks are processed faster than lights. The Journal of neuroscience : the official journal of the Society for Neuroscience 31(23): 8654-8.
2) Komban, S. J., J. Kremkow, J. Jin, Y. Wang, R. Lashgari, X. Li, Q. Zaidi and J. M. Alonso (2014). Neuronal and perceptual differences in the temporal processing of darks and lights. Neuron 82(1): 224-34.
3) Wool, L. E., S. J. Komban, J. Kremkow, M. Jansen, X. Li, J. M. Alonso and Q. Zaidi (2015). Salience of unique hues and implications for color theory. Journal of vision 15(2).

What’s New

Version 1.0

This app has been updated by Apple to display the Apple Watch app icon.

App Privacy

The developer, Jose-Manuel Alonso, has not provided details about its privacy practices and handling of data to Apple.

No Details Provided

The developer will be required to provide privacy details when they submit their next app update.


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

You Might Also Like