three-dimensional Frog image used to strengthen the binocularity system, to provide Base-In & Base-Out training - can be used in conjunction with Chain Variable Vectograph or Gem Variable Vectograph for supplemental exercises to further strengthen the binocularity system - Vectograph range of 5300 seconds of arc of stereopsis depth - Frog image range of 2500” of stereopsis depth - total accommodation range of 40 diopters - with Polarized Viewers and plastic support