Heterophoria is the relative deviation of the eyes in absence of fusional vergence. Fusional vergence can be deprived by. for example. occluding one eye while the other fixates a visual target. https://www.roneverhart.com/Samsung-Galaxy-Tab-S9-FE-12-4-in-Tablet-128-GB-Gray-2023-SM-X610NZAAXAR/