Strabismus - Fundamentals of Clinical Ophthalmology.pdf

CONSEQUENCES OF BREAKDOWN OF BINOCULAR VISION
Figure 3.1 Anomalous retinal correspondence
(ARC). ARC occurs when the fovea (black cross) of
the fixing eye is paired with a non-foveal point of the
fellow eye so that they acquire a common visual
direction in order to visualise an object (red triangle).
The fovea of the non-fixing eye is suppressed
be coming from the same direction in space.
Normal retinal correspondence occurs if each of
these points on each retina has the same spatial
relationship with the fovea of each eye.
Anomalous retinal correspondence (ARC)
occurs if there is a different spatial relationship
between these points and the foveas in each eye;
this may be a consequence of long-standing
ocular deviation in children (Figure 3.1).
Sequelae of strabismus in the
mature visual system (adults)
Visual confusion
Visual confusion arises from simultaneous
fovea-dominated perception of two different
images superimposed upon each other, as in the
presence of ocular misalignment. Objects that
are separated in real space are perceived to
belong to the same location in subjective space.
Visual confusion is associated with ocular
Figure 3.2 If corresponding points, for example,
each macula (black cross), are simultaneously
stimulated by different objects (triangle and dark grey
cross), confusion may arise
misalignment, is transient in children and more
likely to be seen in the adult (Figure 3.2).
Diplopia
Diplopia or double vision occurs when an
image simultaneously falls on the fovea of one eye
and a non-foveal point on the fellow eye, usually
from ocular misalignment. The same object
is seen as having two different locations in
subjective space, with the foveal image clearer
than the non-foveal image. Diplopia may
result in suppression in the younger patient
(Figure 3.3).
“Horror fusionis” is an intractable form of
diplopia where there is both a loss of ability to
maintain fusion and an absence of suppression;
this may occur after head injuries, surgical
correction of monocular cataract in adults
with previous suppression, or after prolonged
15