1. Download the app on your iPad and/or your iPhone.
2. Close one eye and adjust the contrast of the corresponding color using the plus/minus buttons on the right hand side until it appears black like the background. Now close the other eye and repeat the process.
3. Hold the device at a distance specified at the top left, 33cm. While looking straight ahead at the screen, attempt to see all 4 dots at the same time. The right eye (red lens) should only see the red dots while the left eye (green lens) should only see the green dots.
4. Note the number of dots you see. If you see 4 dots, your eyes are aligned and you are fusing. If you see 3 dots, your brain is ignoring (suppression) your right eye (red lens on the right side). If you see 2 dots, your brain is ignoring (suppression) your left eye (green lens on the left side). If you see 5 dots, note if the red dots are to the left or to the right of the green dots.
5. If the red dots are on the left side, then you have outward deviation (exo). If the red dots are on the right side, then you have an inward deviation (eso). If you see anything other than 4 dots, momentarily close your eyes or blink quickly.
6. Attempt to realign your eyes in a way that will allow you to see all 4 dots at the same time.
7. Perform the exercise from a distance of 33cm.
8. Repeat exercise from a distance of 3 ft.
9. Perform the exercise from a distance of 6ft.