DVD Flashcards
What is DVD
an anomaly that occurs due to dissociation. They eye under the cover elevated but it returns to its original position on removal of the cover
Associated features
Extorsion and latent nystagmus, infantile esotropia may be associated features.
DVD following surgery
DVD is often noted following surgery for the horizontal deviation, but still occurs if left untreated
Aetiology
Its unknown but its related to infantile ET and is thought to be related to the early disruption of binocular function. Its supported by the development of DVD in monkeys with induced ET. Further study- Guyton (2000). Brodksy 2002 found that DVD is a human dorsal light reflex. This demonstrated a perceptual tilt of an object when one eye was occluded resulting in a cyclovertical divergence of the eyes to compensate.
Features
Fixation is required for DVD to be elicited first described by Posner (1944) and later confirmed by Spielmann (1986). Extorsion, latent nystagmus, abnormal monocular OKN
Tychsen et al 2009- Investigated OM signs in strabismic monkeys (read)
Investigating DVD
Case history- often infantile ET, limited elevation
AHP- Head tilt to fixing eye
CT- torsion, latent nystagmus, prolonged dissociation shows max angle, larger in distance, hypodeviation may be initially present, Any component may be the largest DHD, DTD whole entity may be referred to as DSC
Investigating DVD
Ocular movements
All defects may be associated, IO o/a can coexist but must not be misdiagnosed, A and V patterns but A is more common and associated with SO o/a. Don’t dissociated too much and may become manifest on versions.
Measurements
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
Bielchowsky darkening wedge test
Fixate to light, occlude one eye(eye will elevate), neutral density filter in front of other eye, increase filter until eye behind cover moves down and then remove filter and eye will elevate again.
Patterns
Maclellan 1971- suggested pattern of events; h dev with/without v dev at 0-3, DVD more marked and demonstrable 3-7, of h dev reduced, DVD more stable however eye intermittently drifts up and symptoms at this stage 7 years +
Harcourt et al 1980- found no significant decrease
Variations
Kraft et al 2006, Lim 2008- Dissociated HoT described and inverse DVD
Lim et al 2008- DVD in patients with Intermittent XT, Had earlier onset of strabismus than those intermittent exotropias without DVD, worse stereopsis, smaller in magnitude
Management of DVD
Refractive correction and amblyopia treatment, surgery and DHD.
Surgery for DVD
Anterior transposition of inferior oblique with recessions
Anterior transposition of inferior oblique with resections
Inferior oblique weakening if overaction coexists
More DVD surgery
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
Surgery timing for infantile ET and DVD
Arslan 2010
The findings of the study by Arslan et al. (2010) on surgery for Dissociated Vertical Deviation (DVD) suggested that surgical intervention on the inferior oblique muscle was effective in improving ocular alignment and visual function in patients with DVD. The study indicated positive outcomes in terms of reducing the deviation associated with DVD and enhancing overall eye alignment following surgery on the inferior oblique muscle.
