disssociated vertical devaition (DVD) Flashcards
what is dvd
DVD is an anomaly which occurs on dissociation.
The eye under cover progressively elevates but returns to it’s original position on removal of the cover.
Extorsion & Latent Nystagmus may be associated features
what is the ateiology of dvd
Unknown - but in view of it’s relationship to Infantile esotropia it is thought to relate to the early disruption of binocular function. Supported by the development of DVD in monkeys reared with induced esotropia
Guyton (2000) demonstrated horizontal and cyclovertical latent nystagmus occurs on occlusion of patients with DVD followed by cycloversion/vertical vergence with the covered eye elevating and extorting. Suggesting the early onset defect of binocular function, occlusion or concentrating on fixing with one eye produces unbalanced input to the vestibular system and results in this nystagmus. The cycloversion / vertical vergence is a mechanism to dampen the nystagmus
how is dvd related to a dorsal light reflex
Brodsky (2002) reported a study supporting the notion that DVD is a human dorsal light reflex. This demonstrated a perceptual tilt of an object when one eye was occluded resulting in a cyclotovertical divergence of the eyes to compensate
what are the features of dvd
Extorsion
Latent Nystagmus
Abnormal monocular OKN
what investigation needs to be done for dvd
Case History
often associated with Infantile esotropia
may notice intermittent elevation
AHP
head posture of head tilt common (usually to fixing eye)
Cover Test
note torsion / latent nystagmus
prolonged dissociation reveals maximum angle
may be larger for distance
a hypodeviation may initially be present
Any component may be the largest DHD, DTD whole entity may be referred to as DSC
what ocular motility defects may be observed in dvd
All types of defects may be associated
Inferior oblique overaction can coexist but must not be misdiagnosed
A & V patterns possible but A more common and often associated with o/a SO’s
Care should be taken not to dissociate too much
May become manifest on versions
what investigation needs to be done
Measurement
PCT simultaneous and alternate
Prism under cover test – strabismus 2018 Klaehn, Hatt, Leske, Holmes
fixing either eye
often no reversal
Synoptophore
Reversed fixation test
Neutralise manifest deviation with PCT
Observe movement of fixing eye as perform alternate Cover Test to diagnose dissociated deviation
If dissociated element present ask pt to hold neutralising prism in front of deviating eye and then neutralise the dissociated movement in the other eye
what Is the bielshowksys darkening wedge test
Fixate light
Occlude one eye (eye will elevate)
Neutral density filter in front of other eye
Increase filter until eye behind the cover will move down
Remove filter & eye elevates again
what is dvd linked to
DVD linked to poor development of binocular function
The majority are associated with infantile esotropia
Early surgical intervention of the esotropia (before 8 months) may limit the development of DVD
Surgical intervention is the management of choice when required but there is a risk of re occurrence
what are the associations between timing go surgery for infertile esotropia and dvd
Very early surgery reduces the severity of DVD & lowers the need for DVD Sx
what is the management of dvd
Order refractive correction
Treat any amblyopia
Surgery
Anterior transposition of inferior oblique with recessions
Anterior transposition of inferior oblique with resections
Inferior oblique weakening if overaction coexists
Large superior recti recessions (10-13mm) recommended if no inferior oblique o/a
Superior recti recessions with posterior fixation sutures
Inferior rectus resection in recurrent cases
DHD
Recession of lateral rectus with or without posterior fixation suture
Bilateral lateral rectus recession
what are the variations of dvd
Dissociated Hypotropia has been described (Kraft et al 2006, Lim 2008)
DVD in patients with intermittent exotropia (Lim et al 2008)
Had earlier onset of strabismus than those intermittent exotropias without DVD
Worse stereopsis
Smaller in magnitude
what is the pattern of dvd
Maclellan in 1971 suggested a pattern of events
horizontal deviation with or without vertical (0-3yrs)
DVD becomes more marked and easily demonstrable(3-7yrs)
If horizontal deviation reduced DVD becomes more stable. However, the eye may intermittently drift up & symptoms experienced at this stage (7yrs & upward)
Harcourt et al 1980 found no significant decrease
DVD is often noted following surgery for the horizontal deviation, but still occurs if left untreated
what can dvd be diagnosed with
Dissociated Vertical Deviation (DVD) is a condition where one eye has a higher resting position than the other when looking at a distance. It can be differentially diagnosed with several other conditions, including:
Superior Oblique Palsy: This condition causes one eye to have difficulty looking downward and inward, resulting in the other eye moving upward and outward to compensate. This can create a similar appearance to DVD.
Brown Syndrome: This is a condition where there is restricted movement of the eye in an upward direction, leading to an upward deviation of the eye. It can also create a similar appearance to DVD.
Duane Syndrome: This condition is characterized by restricted eye movement, resulting in one eye being unable to move inward. This can cause the other eye to drift outward, leading to a similar appearance to DVD.
Congenital Fibrosis Syndrome: This is a group of conditions that affect eye movement and can cause an eye to be in a higher resting position than the other eye, leading to a similar appearance to DVD.
