Dissociated Vertical Deviation (DVD)

INTRODUCTION:
 DVD describes the condition in which either eye, or
occasionally only one eye, elevates when the amount
of light entering it is reduced, for example by an
occluder during the cover test. The elevated eye
returns to its original position when the cover is
removed.
 The cover test must be performed slowly, covering
each eye long enough to allow elevation of the
covered eye to occur.
 DVD is often easier to see when the patient fixes on a
distance target.

Dissociated Vertical Deviation

Dissociated vertical deviation, left eye.
Center, A large left hyperdeviation immediately after the eye is
uncovered.
Left eye drifts back down toward horizontal.

Other terms:
 Helveston (1980) listed 16 synonyms for DVD: the
terms most widely used in the recent past are.
1. Dissociated vertical divergence
2. Alternating hyper ( phoria / tropia )
3. Alternating sursumduction
4. Double hypertropia

 DVD is an acquired condition.
 Usually develops between the ages of 18 months
and 3 years.
 It is rarely seen under 1 year of age but can
occur as late as 5 or 6 years.
 Its onset is therefore later than the associated
strabismus and nystagmus.

 The onset is gradual,
 Sometimes preceded by a unilateral or bilateral
alternating hypertropia.
 Several weeks or even months observation may be
needed before the diagnosis can be confirmed.

CHARACTERISTICS / FEATURES:
Slow upward deviation of one eye spontaneously
during periods of visual inattentiveness or when
occluded.
The upper eyelid position does not change.
The eye seems to float “downwards” on removal the
cover, often to more hypotropic position than normal,
and slowly reverts to original position.

Cont…
 Eye which elevates often shows extorsion.
 Horizontal deviation may reverse under the cover,
e.g. in a left esotropia the left eye under the cover
deviates upwards and horizontal deviation changes
to divergent position, with extorsion.
 DVD frequently more marked for distance than for
near.

Cont…
It is usually bilateral, but may be so asymmetrical that
it appears virtually unilateral.
May be associated with binocular single vision or a
manifest deviation.
DVD can be superimposed on a true vertical
deviation .
DVD does not follow Hering’s law of motor
correspondence, so no associated hypotropia of the
fellow eye can be observed

Cont…
Most commonly associated with early onset esotropia.
But can coexist with other constant and intermittent
esodeviations or exodeviations and has been reported
as an isolated phenomenon.
Frequently associated with latent or manifest
nystagmus.

An abnormal head posture is commonly found,
especially when associated with nystagmus(face turn
to fixing eye, also head tilt towards fixing eye has
been described).
Rarely condition decompensates into large manifest
hypertropia.
Spontaneous decompensation may be seen
intermittently.
DVD is not seen in association with high grade
stereopsis and central binocular vision.

 Either an A- or a V-pattern may be present , but an A-
pattern is more common.
 Binocular vision is likely to be weak. Absent or
defective fusion is present (peripheral fusion only)
investigation of binocular functions require least
dissociating tests possible (Bagolini, Lang Stereo test)

Bielschowsky phenomenon
(darkening wedge test):

 This test was designed specifically to diagnose the
presence of DVD.
It can be also used to differentiate between DVD and
inferior oblique over function.
The principle is gradually to reduce the amount of light
entering the eye: a graded wedge was originally used
but a neutral-density filter bar is the suitable alternative.
The patient fixates a light and the non fixing eye is
occluded, hence the eye behind the occluder will
elevate. The filter is introduced in front of the fixing eye,
starting with the lowest filter, and the density is slowly
increased.

 As the light entering the eye is reduced, the eye
under the cover will be seen to move down,
possibly dropping below the mid-line. As the filter
density is reduced the eye under the cover will
progressively elevate again.
 The test requires quite prolonged fixation, which
makes it difficult to use with young children,
 and it can only be demonstrated in approximately
50% of patients with DVD.

Optokinetic nystagmus testing:
 Use catford drum
 Occlude each eye in turn.
 Rotate the drum to move the dots from temporal to
nasal side.
 Reverse the drum to rotate the dots from nasal to
temporal.
 Carefully observe the elicited optokinetic response

Patients with DVD will show abnormal optokinetic
response.
The nystagmus response from temporal to nasal is
normal.
The response from nasal to temporal will be absent or
reduced compared to the temporal to nasal side.

 Abnormal optokinetic response may be of value
to predict those cases of congenital esotropia
likely to develop DVD later (asymmetrical
optokinetic response is seen prior to
development of DVD)

Measurement of the DVD:
Accurate measurement is difficult to obtain because
of the progressive nature of DVD.
When attempting to quantify DVD each eye has to be
measured separately.
Measurement of the DVD can be obtained using an
alternate prism cover test with each eye fixing in turn
to record the degree of asymmetry.
Prisms are placed base down before the eye to be
measured until it no longer rises behind the cover.

 It may be impossible to reverse the deviation to
check the accuracy of the measurement but the
maximum amount of elevation can be recorded.
 Even with this method, DVD measurements are
variable day to day and even moment to moment,
and tend to increase with prolonged occlusion.

 Correct the refractive error and treat amblyopia if
present.
 A manifest strabismus is treated as indicated.
 Hypertropia in DVD that is only evident intermittently
and is small in size ( < 15 PD) does not require
treatment.
 DVD rarely causes symptoms, but it can be
disfiguring since even small hyperdeviations will
appear prominent as sclera begins to be visible at
the lower eyelid margin

Surgery Option:
 DVD is managed surgically when necessary.
 Surgery is indicated if there is frequent and
persistent spontaneous elevation of one or both
eyes, which can be very unsightly: it is required in
relatively few cases (10%).
 The purpose of the surgery is to reduce the
frequency and size of the manifest phase and it is
performed for cosmetic purposes.
 Surgery aims to weaken the eye’s elevating force
or strengthen the depressing force by operating
on the relevant cyclovertical muscles.

The choice of surgery is influenced by:
1) Associated inferior oblique over action
2) Whether DVD is bilateral or unilateral
3) The degree of asymmetry in bilateral DVD
4) The presence of an A-pattern with overacting
superior oblique muscles.

 DVD With Over action Of The Inferior Oblique
Muscles:
 A V-pattern with over action of both inferior oblique
muscles was present in 10% of the cases of DVD 
 Bilateral recession with antero-positioning procedures.
 If a truly unilateral DVD is present which measures at
least 15-20 A of hypertropia in the primary position,
then a unilateral procedure can be performed on the
overacting inferior oblique muscle.

 Bilateral Or Unilateral DVD Without Inferior
Oblique Over action:
 In unilateral cases the amount of superior rectus
recession can be graded according to the size of
the hypertropia.
 Surgery comprises a bilateral superior rectus
recession of 10-13 mm in bilateral symmetrical
DVD.

 DVD With Over action Of The Superior Oblique
Muscles:
 An A-pattern with over action of both superior oblique
muscles was present in 30% of cases of DVD.
 The A-pattern is managed by weakening the action of
the superior oblique muscles, usually with a posterior
tenotomy,
 and the DVD is managed by superior rectus
recession, performing both procedures in one sitting.

• DVD is a bilateral condition but may be
asymmetric.
• There may be apparent or true inferior oblique
overactions.
Ocular motility:

DVD I . O overaction
1 Cover Test Hyperdeviation remains the
same in primary position and
contralateral versions
Intorsion on refixation
Progressive elevation
Hyperdeviation increases
on contralateral versions
No torsion noted
Constant degree of
elevation
2 Ocular motility Sudden upshoot on
contralateral versions when nose
intervenes
Elevation under cover equal in
all positions of gaze
Gradual updrift on
contralateral versions.
Greatest elevation on
adduction
3 Latent
Nystagmus
Usually present Less often present
4 A/V patterns
Bielschowsky
Phenomenon
Mainly A pattern
positive
V Pattern often present
Negative5
Differential diagnosis between DVD and inferior oblique overfunction:

Dissociated Vertical Deviation (DVD)

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Dissociated Vertical Deviation (DVD)