Approach to a patient with diplopia
Dr. R.R.Battu
Narayana Nethralaya
What does the faculty of BSV
require?
– Perfect ( or near perfect ) alignment of the
visual axes simultaneously on the object of
regard
– Perfect ( or near perfect ) retinal
correspondence
– Perfect central ( or paracentral ) fusional
capability.
– Perfect ( or near perfect ) alignment of the
retinal receptors
– Perfect ( or near perfect ) optics to allow
only one image to be formed on the retina
and the same single image to be formed on
the other
What is Diplopia ?
 It is when more than one image ( two ) of the
object of regard are seen simultaneously
 This occurs when….(Mechanisms)
– More than one image of the object of regard is formed
in the retinae of one or both eyes ( monocular
diplopia)
– The eyes lose their simultaneous alignment with the
object of regard in one or more directions ( or
distances ) of gaze (incomitance of ocular alignment –
binocular diplopia)
– The eyes although aligned, send images to the brain
which disallow fusion ( aniseikonia )
– Local retinocerebral adaptations to misalignments in
early life go askew (paradoxical diplopia, loss of
suppression)
– Rarely, purely cerebral mechanisms
Monocular vs Binocular Diplopia
Key question
Is the double vision present even on
monocular eye closure?
Monocular diplopia
 More than one image of the object of
regard is formed in the retinae of one or
both eyes…..
– Irregular astigmatism ( nebular scars, haze,
corneal distortion)
– Subluxated clear lenses
– Poorly fitting contact lenses
– Early cataract
– Iridodialysis, polycoria, large iridotomies
– Macular disorders – edema, CNVM etc
Binocular Diplopia
The eyes lose their simultaneous alignment with the
object of regard in one or more directions ( or
distances ) of gaze (incomitance of ocular alignment –
binocular diplopia)
Key clues
Anomalous Head Position
Vision Blurry in one gaze position, better in another
Vestibular signs
Long tract signs
Obviously misaligned eyes, proptosis
Presence of partial ptosis
Nystagmus
Questions to be asked
Is there a mis alignment?
If so, in which directions ( or
distances ) of gaze?
Which are the hypofunctioning (
and hyperfunctioning ) muscles?
Do they have a neurogenic pattern,
or a restrictive pattern or a
neuromuscular pattern or a
myogenic pattern?
Identifying muscle/s involved
AHP
– Predominant face turn – horizontal
recti
– Predominant chin elev/dep – vertical
recti, pattern strabismus
– Predominant tilt – Obliques
Diplopia Key questions
Is the diplopia more for distance or near?
Is the diplopia predominantly horizontal or
vertical?
In which direction of gaze are the images
maximally separated?
To which eye does the “outer” image
belong?
Is there a predominant tilt?
In which position of gaze does the tilt
increase maximally?
Diplopia charting
Diplopia is maximum ( separation
of images) in the field of action of
the paralysed muscle.
The false image ( the image
belonging to the eye with the
hypofunctioning muscle ) is always
peripherally situated
– Higher in upgaze, lower in downgaze,
on the right in right gaze and on the
left in left gaze
Hess Charting
Based on the principle of confusion
Allows for identifying the position
of one eye, while the other eye fixes
in different positions of gaze.
Effectively demonstrates
Sherrington’s and Hering’s laws
Allows for more objective follow up
also.
The cover-uncover and alternate
cover tests
Probably the most important
objective tests to evaluate muscle
palsies
Measurements with a prism bar
allow for measurement
Measure in the 9 cardinal gaze
positions
Distance and near
Versions & Ductions
Allow to assess actual rotation
limits
Allow assessment of underactions
and overactions of synergists
Saccadic Velocity
“Floating saccades” are suggestive
of a nerve palsy or paresis
Indirectly “oblique saccade” testing
can be done.
Normal saccadic velocity with
limitation indicates a restricted
muscle
Forced Duction Testing
Allows to assess forced movement
in direction of restriction
– Important in Blow out fractures, TED,
long standing strabismus with
contractures
Important to lift the globe and rotate
Force Generation Testing
Allows to identify residual power in
a suspected paretic muscle.
Usually done to direct management
– 6th N palsy
• Recess – resect or muscle transposition
Pointers to primary orbital disease
Restrictive muscle hypofunction
Proptosis
Signs of orbital inflammation
Signs of anterior segment, lid and
adnexal hyperemia or inflammation
Neurological disease
 Look for supranuclear, nuclear and
infranuclear patterns
 Look for sensory ( visual ) abnormalities
 Look for nystagmus
 Look for vestibular – auditory symptoms
 Look for other cranial nerve involvement
 Look for long tract signs
CNS and orbital imaging
Done for obvious neurological
patterns
Orbital inflammatory disease,
proptosis
Occasionally may avoid or delay
– Pupil sparing 3rd in a diabetic
– 6th Nerve in a hypertensive, image if
no spontaneous recovery in a few
weeks
Imaging
CT
MRI
– Fat suppression
– Stir sequences
MRA vs CT angio
Ancillary tests
Tests for myasthenia
Tests of thyroid function
X- ray chest
Bloods
Aniseikonia
Occurs when image size disparity
exceeds 5%
Previously seen in monocular
aphakia
May occur following
keratorefractive surgery
Convergence insufficiency
Classically for near
Could be primary or secondary
Others
Suppression scotomas
Decompensated squints with
Anomalous Retinal
Correspondence
Paradoxical diplopia