Binocular vision refers to the ability to coordinate the use of both eyes to perceive a single visual image. It involves three grades - simultaneous macular perception, fusion, and stereopsis. Fusion is the ability to perceive two slightly disparate images as one coherent image. Stereopsis provides three-dimensional depth perception. Benefits of binocular vision include single vision, enhanced depth perception, enlarged visual field, and compensation for blind spots. Retinal correspondence refers to matching retinal points between the eyes. Normal correspondence matches the fovea and temporal/nasal retina, while abnormal correspondence can occur with strabismus. The horopter and Panum's fusional area describe the region of single binocular vision. Fixation

2. The ability to maintain visual focus
on an object with both eyes,
creating a single visual image.

3. The state of simultaneous vision,
which is achieved by the coordinated
use of both eyes.
 so that separate and slightly
dissimilar images arising in each eye
are appreciated as a single image by
the process of fusion

4. Grades of Binocular Vision:
 Simultaneous macular perception
 fusion
 stereopsis

5.  Grade I: Simultaneous macular
perception
 the ability to see an image simultaneously
with both eyes
 is the most elementary type of binocularity.
It occurs when the visual cortex perceives
separate stimuli to the two eyes at the same
time and concerns itself

6.  Grade II: fusion
Ability to fuse two slightly disparate
images into a coherent whole.

7. Grade III: stereopsis
three-dimensional depth perception

8.  The advantages of a Binocular vision
1. The first and the foremost advantage of a
binocular vision is single vision.
2. In addition to single vision it results in stereopsis
– the most precise kind of depth perception
3. Enlargement of the field of vision
4. Compensation for blind spot and other
differences

9. Retinal Correspondence
Retinal elements of the two eyes that
share a common subjective visual
direction are called corresponding retinal
points.
All other retinal elements are non-
corresponding or disparate with respect
to a given retinal element in the fellow eye
for a particular visual direction.

10. Retinal Correspondence
1. Normal Retinal Correspondence
2. Abnormal Retina Correspondence

11. Normal Retinal Correspondence
 Retinal correspondence is called normal
when both the fovea have a common visual
direction and the retinal elements nasal to
the fovea in one eye corresponds to the
retinal elements temporal to the fovea in the
other eye.

12. Abnormal Retinal Correspondence
 Retinal correspondence is abnormal when
the fovea of one eye has a common visual
direction with an extrafoveal area in the
other eye. This is generally seen if the angle
of squint is small and the extrafoveal point
is close to the fovea

13. Concept of a Horopter
 In normal binocular vision, both eye fixate
the same object point, this point will be
imaged on corresponding retinal elements
of the two eyes –the foveae.
 Ta the same time, there will be other object
points in space besides the fixation point
that also will be imaged on corresponding
retinal elements of the two eyes.

14.  If the position of these other points is
determined theoretically a circle will be
found passing through the entrance pupils of
the two eyes. This circle is known as the
theoretical or geometrical horopter

17. Panum’s area
 The field in front of and behind the
horopter , in which the expected diplopia
does not occurs is known as panum’s
fusional space

20. Fixation disparity
 During binocular fixation, the point of
fixation is rarely ever imaged exactly on
corresponding points of the two foveae but
that the primary line of sight of one eye
misses the fixation point very slightly, being
either under converged or over- converged.
this phenomenon is called

22.  Binocular rivalry
 When very different images are shown to the
same retinal regions of the two eyes,
perception settles on one for a few
moments, then the other, then the first, and
so on, for as long as one cares to look. This
alternation of perception between the
images of the two eyes is called binocular
rivalry.

24.  Two dissimilar objects located in the same
plane give rise to a conflict or confusion .
 Contradictory and incompatible signal are
transmitted from corresponding points to
the visual cortex is termed retinal revairy

25. Thank you