Write a short note on Panum's Vision and Physiological Diplopia.

Panum's Vision and Physiological Diplopia are related concepts in binocular vision:

• Panum's Vision (or Panum's Fusional Area): This refers to the small range of retinal disparities (differences in the images projected onto each retina) within which the brain can still fuse the two images into a single, coherent perception of depth. Objects whose images fall within this area are perceived as single and in depth.
• Physiological Diplopia: This is the normal, non-pathological phenomenon of seeing double images of objects that are either significantly closer or significantly farther than the point of fixation. This occurs because the retinal images of these objects fall outside Panum's fusional area, meaning their disparity is too great for the brain to fuse them into a single percept, resulting in perceived double vision.