Vergence Skill Building: This activity is designed to train Vergence skills though repetition and small, steady improvement of range of motion/fusion and narrowing the gap between breaks and recoveries. Measurements in this activity are approximate. For more accurate diopter measurements, please consult your OD. Please review directions and activity with patients before assigning for home use, and tell them approximately how long to work their Base In and Base Out ranges, if you have goals for timing.