Pendular nystagmus due to retinopathy

While pendular nystagmus (PN) should always make the examiner consider oculopalatal tremor, multiple sclerosis, among rarer conditions such as drug or medication toxicity (e.g., toluene), PN may also result from vision loss. While this is often attributed to infantile nystagmus, visual deprivation in adulthood can also cause PN, perhaps due to a loss of visual (afferent) calibration at the level of the neural integrator network/gaze holding machinery. This patient experienced progressive vision loss due to achromatopsia, and a disconjugate nystagmus can be seen here - mainly torsional in the better seeing right eye, and elliptical and more symptomatic in the worse seeing left eye. MRI and neurologic work-up was normal without evidence of demyelination, and there was no palatal tremor.