Fusional Vergence Amplitude - Arabic Language
Notes:
*The bar prism must be mounted in fornt of non-deviated eye
*We only add it binocularly using the phoropter (1DP / Second)
*In reality, the eye follows the image in the direction of the apex of the prisim, while the light rays are bent toward the prism base, so the motor fusion system send signals to redirect the eye in the opposite direction of the apex to maintain the fusion (the greatest prismatic power that the eye can adapte, maintaing the fusion in the same time, is called vergence amplitude)