Rotary Nystagmus

Here are two videos of a child attempting fixation on the internal target of an autorefractor (hot air balloon at end of road).  Rotary nystagmus is evident, greater with the right eye fixating than the left eye.  Monocular visual acuities are 20/100 right eye and 20/50 left eye due to an increased latent component, utilizing isolated numbers as the acuity demand. When viewing monocularly, there is head turn to the right and gaze left to seek a null point.  When viewing binocularly, acuity approach 20/20.  This child had strabismus surgery at age 2, and is now 10 years old, with a variable right exotropia and constant suppression of the right eye on sensory testing with anagylphic or polarized targets.  The term “cogwheel” is generally reserved for pursuits, but in a sense better describes the attempt to maintain fixation on a target, with drifts and then corrective saccades back to the target.

Right Eye:

Left Eye:

The child wear a plus lens Rx for moderate hyperopia of +2.00 OD and +1.50 OS.  Maintenance of BVA right eye will be through MFBF activities which will trigger less latent nystagmus than occlusion.  That presents a middle ground through which fusion may ultimately be achieved.

4 thoughts on “Rotary Nystagmus

  1. Looks like also a prominent latent nystagmus, assuming it isn’t present under binocular aspects. This would suggest infantile eT. Are his pursuits better temporal to nasal vs. nasal to temporal monocularly?

    • Yes, Curt. Infantile ET with consecutive XT post-surgically. There is a latent component to the nystagmus horizontally. His pursuits are variable due to the post-surgical RXT, but the strong head turn to the right for doll’s eye fixation nasally with the right eye, rotating inward to the nose, attests to the strong temporal to nasal bias due to nystagmus null zone in that direction. Auto-refraction puts the patient in a quasi latent state, fixating the target with one eye and having the other eye suspend fixation but not while occluded in conventional sense.

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