THE AUTHOR HAS NO FINANCIAL INTEREST IN THE SUBJECT
MATTER BEING PRESENTED
• Donders: Abnormal accommodative /convergence ratio and hyperopia
• Duke-Elder: Failure in the development of the secondary fixation reflex;
disruptions of the central, peripheral and postural oculomotor mechanisms; and
impaired development of the optical, sensory or motor systems
• Scobee: Innervational, accommodative, mechanical, functional, sensory and motor
CAUSES OF STRABISMIC DEVIATION
•More than one cranial nerve deficit
•Pupillary involvement of any degree
•Any neurologic symptoms or signs besides
• Divergence insufficiency is an ocular motor anomaly characterized by horizontal
diplopia in the distance.
• The esodeviation remains comitant in all fields of gaze at distance and markedly
lessens or resolves at near.
• Ductions are full without evidence of abduction deficit.
• A cluster of cells in the pons called the nucleus reticularis tegmenti pontis may
represent the supranuclear divergence center.
DIVERGENCE INSUFFICIENCY AND PARALYSIS
• Divergence insufficiency arises as a benign phenomenon with
spontaneous resolution in many cases.
• Neuroimaging should be considered because bilateral sixth
nerve palsies, mass lesions, and demyelinating disease may
• Convergence insufficiency is a relatively common cause of diplopia at near in children and adults.
• It can develop after head trauma
• Patients report diplopia, blurred vision, and asthenopia with prolonged near tasks.
• Examination reveals an exodeviation greater at near than distance and a remote near point of
convergence of greater than 6 to 8 cm.
• Simple eye exercises (“pencil pushups”) are effective in a minority of cases.
• Orthoptic training using base-out prisms for near viewing.
CONVERGENCE INSUFFICIENCY AND PARALYSIS
• Nonorganic cause of double vision, but it might easily be mistaken for a
unilateral or bilateral sixth-nerve palsy or myasthenia,
• Miotic pupils, in a patient with variable esotropia and abduction deficits, can
suggest convergence spasm
• When evaluating versions, there may be an abduction deficit and the pupils are
miotic from convergence.
• When ductions are performed, the abduction deficit resolves.
• Prenuclear vertical misalignment that results from brainstem or
• It may be comitant or incomitant
• Some patients may note diplopia soon after ocular surgery
because a preoperative ocular misalignment failed to cause
diplopia (due to poor vision in the preoperative eye).
• Postoperative refraction may reveal an inter-eye difference
of approximately 3 to 4 diopters (6% to 8% aniseikonia)
while cover testing shows orthophoria.
• Anisometropia induces different prismatic effect between
eyes leading to diplopia.
POSTOPERATIVE DIPLOPIA CATARACT SURGERY
• This is usually vertical diplopia due to small fusional
amplitudes and may be correctable with a slab- off prism from
the more-minus or less-plus lens.
• Other patients suffer from surgical trauma to the EOMs after
peribulbar injections or superior rectus bridle sutures.
• The deviation either resolves within the next several days to
weeks or evolves into a permanent restrictive strabismus
• Diplopia can result from scleral buckling surgery.
• Expansion of hydrogel explant material may cause a restrictive orbitopathy.
• Temporary strabismus lasting several months is not uncommon even after
• However, permanent strabismus may occur from inaccurate reattachment of
the EOM, direct injury to the EOM, and scarring of Tenon’s capsule.
• Scleral buckling can induce a myopic shift in the affected eye leading to
anisometropia and aniseikonia.
SCLERAL BUCKLING SURGERY
• Binocular diplopia may occur after glaucoma implant surgery.
• This complication was much more common with the early Baerveldt
implants than with the Ahmed or Molteno implants.
• Implant reservoirs result in a bleb that may involve the extraocular
muscles; therefore, repositioning the implant may eliminate diplopia.
• If diplopia persists, it may require implant removal.
• Patients can report monocular or binocular diplopia after refractive surgery
• Wavefront technology can measure higher-order optical aberrations, which
have been associated with monocular diplopia.
• Scarring, under/overcorrected refractive error or ablation zone smaller than
the scotopic pupil.
• Binocular diplopia may result from a decentered ablation zone in one eye.
• Maculopathies such as epiretinal membranes can anatomically pull one fovea out
of correspondence with the fellow fovea.
• This misalignment of foveas leads to central binocular diplopia.
• Patients may note relief of diplopia initially (central fusion) with prism trials.
Within minutes, peripheral fusion takes over and the central diplopia returns.
DRAGGED-FOVEA DIPLOPIA SYNDROME
For monocular diplopia refraction, slit lamp and dilated fundus examination is to be done
to find out the cause.
The evaluation of binocular diplopia includes:
1. Abnormal head posture-
The patient prefers a head posture in which the ocular deviation is least and the images can
It has three components :
(a) Chin elevation or depression (vertical)
(b) Face turn to right or left side (horizontal)
(c) Head tilt to right or left shoulder (torsional)
Comparison with an old photograph is helpful to differentiate whether head posture is
long standing or recent.
• Orbital and lid abnormalities –
• Examine lid and orbit for proptosis,
• Periorbital swelling,
• Ocular trauma,
• Lid retraction,
• Lid lag
• Other signs of thyroid associated ophthalmopathy
3.Extraocular muscle movements – Ocular movements ductions and
versions should be checked in all nine positions of gazes.
4. Pupillary reactions – Pupillary examination is vital as its
involvement indicates third nerve palsies due to compressive lesions or
AV malformations and sparing indicates cases of third nerve palsies due
to ischaemic causes.
6. Examination of cranial nerves especially third, fourth and
sixth cranial nerves
7 Third cranial nerve palsy Pupil involving third nerve palsy-
neuroimaging to rule out a aneurysm
Pupil sparing third nerve palsy -due to ischemia secondary to
micro vascular disease like DM, HTN and dyslipidemia
8. Fourth nerve palsy Fourth nerve palsy causes diplopia that
is worse in downgaze. Park – Bielschowsky 3 – step test is an
algorithm for identifying patterns of ocular motility that
confirm the dysfunction of cyclovertical muscles.
c) Sixth nerve palsy The sixth cranial nerve innervates lateral rectus,
which is an abductor. Hence with the normal eye fixing, the paralysed
eye is deviated inwards.
7. Prism Bar Cover Test - Measurement of angle of deviation to quantify
the amount of deviation in different gazes should be done.
8. Maddox rod test – This gives a quantitative information about the
degree and type of ocular misalignment.
9. Fundus examination
• HEAD POSTURE
• Lid fissure: Palpebral fissure
• Facial symmetry
• Chin elevation/depression(vertical)
• Face turn right/left(Horizontal)
• Head tilt to right/left(torsional)
• Ocular torticollis, nystagmus,
• Marcus Gun phenomenon
• Bell’s phenomenon
Head posture in rightsuperior
The chin is down and the headtilted
left while the eyes look up to the
right. This compensates for boththe
vertical and the torsional defect.
Brown right eye
Face Up - Left
SR palsy or IR restriction one or
both eyes chin up
IR palsy with limited depression one or both
eyes Chin Down
Subjective assesment is made on a
scale of 7 points+3 to -3 or 9 points
+4 to -4.
Adduction is normal when nasal
1/3rd of cornea crosses lower
Abduction is normal temporal
limbus touches the lateral canthus.
LIMITATION OF MOVEMENTS
AN EXAMPLE OF PARALYTIC VERTICAL
STRABISMUS OF RIGHT INFERIOR RECTUS M.
The prism bar is placed on fixating
eye to neutralise the amount by
observing corneal reflex in non
Differentiates bifoveal fixation from
central suppression scotoma
1.In bifoveal fixation,prism is placed base
outwards with deviation of image
temporally and movements of both eyes
2.In left microtropia patient fixes target
and a prism is placed base out before left
eye.Image moves temporally in left but
within central suppression scotoma.
4 PRISM TEST
Parks three-step test is very useful in the diagnosis of fourth
nerve palsy and is performed as follows :
A- first step. Assess which eye is hypertropic in the primary
Left hypertropia may be caused by weakness of one of the
following four muscles : one of the depressors of the left
eye ( superior oblique or inferior rectus ) / elevators of the
right eye ( superior rectus or inferior oblique ) .
In a fourth nerve palsy the involved eye is higher .
B- step two . Determine whether the left
hypertropia is greater in right gaze or left gaze .
Increase on right gaze implicates either the right
inferior rectus or left inferior oblique .
Increase on left gaze implicates either the right
superior oblique or left superior rectus ( in fourth
nerve palsy the deviation is Worse On Opposite
Gaze – WOOG ).
C- step three .the Bielschowsky head tilt test ( isolates
the paretic muscle ).
With the patient fixating a straight ahead target at 3
meters, the head is tilted to the right and then to the left
Increase of left hypertropia on left head tilt implicates
the left superior oblique and increase of left hypertropia
on right head tilt implicates the right inferior rectus .
( in fourth nerve palsy the deviation is Better On
Opposite Tilt – BOOT )
• In cases of misalignment,subject
• Diplopia can be tested by red green
glasses over right and left eye
respectively with a slit target.
• Esodeviations cause uncrossed
exodeviations cause crossed
• Hess Screen is also used for ocular
paralysis and restrictive conditions.
DOUBLE MADDOX ROD
TEST one white and other
red,tilt neutralised by rotating
the rods.Change in axis givees
the exact cyclodeviation.
Indirect Ophthalmoscopy and
fundus photography are useful.
Double Maddox rod test
-Red and green Maddox rods , with the cylinders vertical , are
placed one in front of either eye .
- Each eye will therefore perceive a more or less horizontal line
of light .
-In the presence of cyclodeviation , the line perceived by the
paretic eye will be tilted and therefore distinct from that of the
other eye .
-One Maddox rod is then rotated till fusion ( superimposition )
of the line is achieved .
-The amount of rotation can be measured in degrees
and indicates the extent of cyclodeviation .
-Unilateral fourth nerve palsy is characterized by less
than 10° of cyclodeviation whilst bilateral fourths
may have greater than 20° of cyclodeviation.
- This can also be measured with a synoptophore .
EVALUATION OF OCULAR TORSION
Anatomic (objective) torsion refers to
anatomic rotation of eye.
Subjective torsion refers to the patient’s
perception of rotation.
Comparison of anatomic and subjective
torsion can help determine the time of onset
of cyclovertical strabismus.
• SUBJECTIVE:Diplopia charting with
slit makes the patient apprecitae tilt.
• Excyclodeviation the tilt will be
anticlockwise and in incyclodeviation
it will be clockwise
• Diplopia is maximum ( separation of
images) in the field of action of the
• 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
• on the left in left gaze
• In a patient with strabismus, the red-glass (diplopia) test involves
stimulation of both
• The fovea of the fixating eye and an extrafoveal area of the other eye.
• First, the patient's deviation is measured objectively.
• Then a red glass is placed before the non deviating eye while the
patient fixates on a white light.
• This test can be performed both at distance and at near.
• If the patient sees only 1 light (either red or white), suppression is
present . the suppression scotoma, causing the patient to experience
• With NRC, the white image will be localized correctly: the white image
is seen below and to the right of the left image .
• With ARC, the white image will be localized incorrectly: it is seen
directly below the image.
THE FOLLOWING RESPONSES ARE POSSIBLE WITH THE
The images appear uncrossed (eg, the red light is to the left of the white light
with the red glass over the left eye).
This response is known as homonymous, or uncrossed, diplopia.
If the patient has exotropia, the images appear crossed (eg, the red light is to
the right of the
white light with the red glass over the left eye).
This response is known as heteronymous, or crossed, diplopia.
If the measured separation between the
2 images equals the previously determined deviation, the patient has NRC.
If the patient sees the 2 lights superimposed so that they appear
despite a measurable esotropia or exotropia, an abnormal localization
of retinal points is present. harmonious anomalous retinal
• If the patient sees 2 lights (with uncrossed diplopia in esotropia
and with crossed diplopia in exotropia), but the separation between
the 2 images is found to be less than the previously determined
deviation, unharmonious anomalous retinal correspondence.
• Corrective prisms are placed in front
of deviating eye with patient fixing
eyes on target.
• Prisms are slowly increased until angle
overcorrected and diplopia occurs.
Sensory adaptation to squint to which
only one eye functions.
1.Bagolini’s striated glasses:
Symmetrical cross response: Absence
of manifest squint(NRC)
Asymmetrical cross response:diplopia
present incommitant squint
Single line:suppresion response of one
Cross response with gap:scotoma
4 dots :normal binocular response
esodeviation:uncrossed pattern(Red on right side)
Exodeviation:crossed pattern(red on left side)
Vertical squint:vertically displaced sets
3 dots:Suppression of right eye
2 dots:Suppression of left eye
WORTH’S FOUR DOT TEST
• Fovea to fovea sensory test
• Each fovea bleached with linear streak of light vertically for 10 sec with
• Linear after image seen.
• Fixing eye stimulated to produce after effect.
• Other eye streak is kept horizontally.
• Patients with NRC see cross(ET,XT)as fovea is centre of refrence.
• In ARC,pseudofovea takes up the centre of reference from peripheral
AFTER IMAGE TEST
• Fovea temporal to pseudofovea,temporal
retina projects in opposite field
• -Right after image.
• Fovea nasal to pseudofovea and nasal retina
projecting to ipsilateral field
• Right after image seen on right.
• Test for suppression
• Patient is asked to read letters on screen with polarised glasses
• Projection of letters has certain letters seen by right eye,some by left and
others by both eyes.
• Patient with normal BSV-Sees all letters
• Suppression if present-Supressed eyes letters not seen.
• Patching therapy pedig trial
• Fresnel prisms
• Black contact lens with dim pupil size
• Photograted glasses
• A new method of treating diplopia that does not have the limitations of
traditional patching has been successfully evaluated.
• The "spot patch" is a procedure that eliminates diplopia without compromising
• It is a small, usually round or oval, patch made of 3-M TransporeTM tape, 3-M
blurring film (or another such translucent tape).
• It is placed on the inside of the lenses of glasses and directly in the line of sight
contributing to the diplopia.
SELECTIVE PARTIAL OCCLUSION
• The "spot patch" works because it effectively eliminates central
vision in the partially occluded eye.
• Diplopia is perceived as a central visual phenomena when the
visual axes do not align.
• The size of the diplopic zone is not known for certain, but is
believed by this author to correspond to Panum's fusional area,
which is approximately 25 by 25 minutes of arc.
• Diplopia does not seem to be perceived outside of this zone.
• Central vision is necessary for examining small areas of detail, visual acuity
• Peripheral vision is necessary for evaluating space in general around the
body, motion detection, orientation and mobility.
• With the "spot patch" central vision is sufficiently blurred to
eliminate the diplopic image, but not completely eliminate
• Peripheral vision is not eliminated with the "spot patch“, the
patient does not lose peripheral fusion/visual field/ the visual
components of orientation, balance and mobility.
• Creates a monocular central scotoma
inversely mirroring the physiological
variation in spatial acuity across the
monocular visual field, suppressing the
diplopia with minimal impact on the
• This simple, inexpensive, non-invasive
device may thus be an effective new tool
in the treatment of a familiar but still
troublesome clinical problem.
Robert MP1, Bonci F2, Pandit A2, Ferguson V3, Nachev P4. The scotogenic contact
lens: a novel device for treating binocular diplopiaBr J Ophthalmol. 2015
Aug;99(8):1022-4. doi: 10.1136/bjophthalmol-2014-305985. Epub 2015 Feb 13
SOFT CONTACT LENS
• Often when patients with anisometropia receive a new pair of glasses, they will
complain of double vision, particularly while reading.
• This double vision is due to the differential prismatic effects of the two lenses when the
patient is looking off-center as when reading (as per Prentice’s Rule)
• . In order to improve reading vision, vertical prism can be incorporated into the lower
portion of one lens or the other to help compensate for the differential vertical
prismatic effect and lessen or eliminate the double vision.
• These prisms are referred to as slab-off or reverse-slab prisms.
• The slab-off prism is placed on the more minus or less plus lens, more commonly on
glass lenses, and in effect takes away base-down prism (adds base-up prism).
• The reverse-slab prism is placed on the more plus or less minus lens, most commonly
on molded plastic lenses, and adds base-down prism.
• Composed of concentric annular rings.
• Principle: the prism apex deviates light just
as much as any other part of the lens.
• Sheet of prism apices on a thin base sheet
used to obtain a prismatic effect across the
lens without creating additional lens
• Method of choice for temporary use. Upto
30° can be applied to either eye but high
powered prisms may not be tolerated.Upto
20° can be worn comfortably
• The prism is normally fitted to the back
surface of the spectacle lens.
• 1980 and 2007in to achieve its desired effect, directly injected into the belly of an
• Operating room under direct visualization or through the use of electromyographic
techniques, though some surgeons do not feel that electromyography use is critical to
the success of the procedure .
• It is supplied in individual vials containing 100 units of freeze-dried toxin. Each unit
contains approximately 0.25 ng of the protein.
• The toxin must be stored in a freezer until it is ready for use. Toxin is prepared for
injection by reconstituting with nonpreserved normal saline.
• Typically, for the treatment of strabismus, the desired concentration is 2.5 units/0.1 ml
Dawson EL1, Maino A, Lee JP. Botulinum toxin may be used to
assess the likelihood of reducing the abnormal head posture and
reducing the diplopia by increasing the field of binocular single vision