This document discusses binocular single vision (BSV) and related concepts: - BSV occurs when the two eyes coordinate to produce a single mental image from stimuli received simultaneously from both eyes. It allows three-dimensional, binocular depth perception. - The horopter defines the locus of points in space that stimulate corresponding retinal points in the two eyes during binocular fixation. Stimulation of corresponding retinal points produces single, fused vision. - Tests like Bagolini's striated glasses and the Worth four-dot test assess ocular alignment and dominance by determining whether stimuli presented to corresponding or non-corresponding retinal points produce single or double vision.

3.  The co-ordinated use
of two eyes to
produce a single
mental impression
when an individual
fixes his visual
attention on an object
of regard.

6.  SMP exists when signals
transmitted from the two
eyes to the visual cortex
perceived at the same
time.
 It consisting of ability to
see two dissimilar objects
simultaneously at the
same time.

7.  Ability of the two eyes
to produce a composite
picture from two similar
pictures each of which
is incomplete in one
small detail

8.  Ability to fuse images
Which are slightly
focused from different
angle result in
binocular appreciation
of visual object in
depth ie: in 3D.

9.  Retinal elements of the
two eyes that shares a
common visual direction.
 Stimulation of the
corresponding elements
of the two eyes produces
a single vision - NRC

10.  Specifically the right nasal retina contains points that
correspond to their counter parts in the left temporal
retina.
LAW OF SENSORY CORRESPONDENCE
Existence of corresponding retinal elements with their common
relative subjective visual direction
Is the essence BSV

11.  When the fovea of one
eye has a common
visual direction with an
extra foveal element in
the other eye.
 Angle of squint small
when the extra foveal
element is close to the
fovea- to regain the
BSV although its
anomalous.

12.  horos – boundary
opter – observer
 Horopter – Horizon of
vision
 Locus of all object points
that are imaged on
corresponding retinal
elements from a given
fixation distance.

13.  If we draw a line
passing through the
corresponding points in
the horopter, we will get
a circle passing through
the centre of rotation of
the two eyes and the
fixation point.

14.  Herring & Hillebrand-
VMC doesn’t describe
longitudinal horopter.
 Flatter than VMC.
 Distribution of
corresponding points –
not the same in nasal
&temporal retina.
 Shape varies

15.  Region infront & back of
the horopter in which
single vision is present.
 Narrowest at the fixation
point& become border in
the periphery at a rate of
1-2 arc minute

16.  Assessment of relationship b/w fovea of the fixing eye
and the retinal area stimulated in the squinting eye .
1. Bagolini’s striated glasses test.
2. Worth Four Dot Test.
3. Synaptophore using SMP slides for
measuring the obj & sub angles .

17. A- NRC
B-RE Suppression
C-scotoma
Double vision with
Exotropia

18. Four Dots
NRC –No Heterotropia
Normal BSV – No manifest Deviation
Harmonimous ARC – Manifest Deviation
Five Dots
Esotropia –uncrossed – red dot to the right
Exotropia – crossed –red to the left of green
Three Green Dot Suppression - RE
Two Red Dot
Suppression - LE

19.  Tested using to
dissimilar pictures such
as an object and a
surround.
Eg :Cage & lion
 Patient is asked to put
the lion in page by
moving the arm of
synaptophore.