Optical Management Using Monovision and Yoked Prism for Acquired Strabismus and Nystagmus Secondary to a Neurodegenerative Disease

[Prism-Induced Gaze Shift and Strabismus Treatment for Ocular Motility Disorders and Anomalous Head Posture]

BACKGROUND

The therapeutic treatment of ocular motility disorders and anomalous head postures (AHP) is often challenging. We report our experience with prism use in these patients.

PATIENTS AND METHODS

Retrospective case series of three patients with ocular motility disorders and associated AHP who were treated with prism correction.

RESULTS

A 37-year-old male with a traumatic left oculomotor nerve palsy suffered from a residual minor depression deficit and a severe elevation palsy. With OS: 10^ base-up he was corrected for left hypotropia only in down gaze. Ten yoked prisms base-up shifted the field of binocular single vision in primary position. A 45-year-old male with traumatic Parinaud syndrome and upward gaze palsy suffered from neck pain due to his pronounced chin elevation. He also had a right amaurosis with secondary exotropia. With OS: 8^ base-up, his AHP was corrected and his neck pain was alleviated. A 69-year-old woman with a left abducens nerve palsy adopted a left turn of 20° to compensate for her deviation in extreme right gaze. With OS: 20^ base-out, her AHP was corrected and she experienced no double vision in primary position.

CONCLUSIONS

Prisms are used to correct strabismic deviations but also can successfully shift images towards another gaze in different clinical scenarios. Reduction of AHP, therefore, can be obtained by a prism-induced gaze shift in the direction of the motility restriction.