Binocular single Vision

  is the coordinated use of two eyes in order to produce a single mental impression.

  Each normal eye sees a clear distant object. However both normal eyes when open simultaneously, they do not see two images of same object. This is called sensory fusion. It takes place at higher nerve centers.It starts developing at birth and established firmly within 7years of age, provided following conditions are met and maintained for first 7years of age.

   1,Image falling on each retina is of same size (anisometropia prevets this)

   2,Image must fall on corresponding  points of retina (squint prevents this).

   3,The eyes, visual pathways and motor nerve supply to muscles of eyes must be normal.

Grades of BSV

    1, Simultaneous perception

    2, Fusion

    3, Steriopsis

 Advantages of BSV

    1,VA improves

    2, Field of vision enlarged

    3, Blind spot of each eye is compensated by the other.

    4, Steriopsis ( depth perception)--- accurate assessment of depth.