Dissociated vertical deviation

This presentation comprises of information regarding dissociated vertical deviation

1. DISSOCIATED VERTICAL DEVIATION (DVD) ANJALI KAVTHEKAR

2. Spontaneous upward turning of dissociated eye DVD syndrome Excycloduction Abduction Latent nystagmus The upward excursion = Dissociated Vertical Deviation The excyclotorsion = Dissociated Tortional Deviation The lateral movement = Dissociated Horizontal Deviation. All 3 components = Dissociated strabismus complex

3. History The term was given byBielschowsky (1938). First described by Stevens as double vertical strabismus Other common names : Alternating hyperphoria (Crone) Anaphoria / anatropia (Stevens) Periodic vertical squint (Anderson) Strabismus sursoadductorius (Cords)

4. Clinical features S ignificant cosmetic blemish. 2-5 years of age The condition is usually bilateral and asymmetric. It is usually associated with : Infantile Esotropia , Sensory heterotropia Duane ‘s retraction syndrome The signs are more profound in an amblyopic, non-dominant or non-fixing eye.

5. The characteristic excursion of the eye : As phoria : Manifesting only under cover As tropia : When it manifests spontaneously, in conditions of fatigue daydreaming, inattentiveness or during poor health.

6. Consequences Cosmetic (Manifest DVD) Longstanding DVD ⇒ SR contracture ⇒ true hypertropia Amblyopia in children Visual disturbances - diplopia , rare

7. Types : Comitant DVD : Vertical deviation (with in ± 7 PD) measures same in abduction, primary position and adduction. Incomitant DVD : Difference in the magnitude of deviation in abduction, primary position and adduction .

8. Measurement of DVD M ild (0-9 PD) Moderate (10-19 PD) Severe (> 20 PD) It is difficult to measure the DVD, as there is change in deviation depending upon the alertness and co-operation of the patient. It is best examined by : Translucent occluder ( Spielmann ) Plus 4 diopter lens

9. I t violates Herring's law of ocular motility. No movement is seen in the fixing eye when the deviated eye returns for re fixation. On uncovering the eye, it slowly drifts back rather than show a rapid re fixation movement as seen in any other hyperphoria or hypertropia .

10. Tests : Hirshberg's test : Gross estimate . Prism Bar Under Cover Test (PBUCT) : Base down prism and a cover is placed in front of the dissociated eye, as the cover is shifted in front of the fixing eye the downward movement of the dissociated eye is noted keep increasing prisms till no movement is seen on switching occlusion

11. Bielschowcky's phenomenon As the intensity of light shown to the fixing eye is decreased, the dissociated eye gradually comes down. Depth of DVD can be measured Suggests sensory component Red glass test The eye under the red glass dissociates and moves upwards. Differentiates DVD from hypertropia

12. Differential diagnosis DVD IOOA Same in primary position, add,abd In adduction and elevation Overaction of SO Underaction of SO Red filter test Bielschowsky's phenomenon Absent Slow redressing movement Range : 2-200 degree/sec Rapid re-fixation movement Range : 200-400 degrees/sec “V ’’ phenomenon may be present "V " phenomenon present

13. A difficult situation can arise when there is DVD in presence of IOOA. In such cases the rapid re fixation movement of the hypotropic eye can be measured with the help of prism bar cover test. Then the total upward deviation may be measured using the PBUCT. DVD is the difference between the two readings

14. Treatment Non surgical Observation Encourage fusion of bifixation Switching fixation Surgical Recession with anterior positioning IO Superior rectus-recession 7-10 mm with or without retroequatorial myopexy Inferior rectus-resection

15. Indications for surgery If DVD is increasing in frequency Phoric deviation is gradually converting to a manifest Head posture to the opposite side indicates a poorer control or a larger magnitude of DVD. Surgery indicated to improve the head posture A large and cosmetically unacceptable deviation

16. Recommended treatment modalities : IOOA & mod. DVD (<5 pd in abduction) Recession with anterior positioning IO IOOA & Severe DVD (>5 pd in abduction) Recession with anterior positioning IO + SR-recession 7-10 mm DVD & no IOOA SR-recession 7-10 mm + IR -resection DVD & SOOA SR-recession 7-10 mm + Posterior tenectomy of SO

17. Points to be remembered : Differentiate from IOOA Patients attention and cooperation to be taken in account Do not miss other eye as it is an asymmetrical condition

18. Thank you