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Br J Ophthalmol 2001;85:1447-1449 doi:10.1136/bjo.85.12.1447
  • Scientific correspondence

Elevated visual motion detection thresholds in adults with acquired ophthalmoplegia

  1. J F Achesona,
  2. L Cassidya,
  3. E A Grunfeld150,b,
  4. J A Shallo-Hoffman151,b,
  5. A M Bronsteinb
  1. aDepartment of Neuro-Ophthalmology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK, bMRC Human Movement and Balance Unit, Queen Square, London WC1N 3BG
  1. J F Acheson jacheson{at}uclh.org
  • Accepted 14 May 2001

Abstract

AIMS To test the hypothesis that in patients with acquired chronic bilateral ophthalmoplegia, abnormal retinal image slippage during head movements would result in abnormal thresholds for visual perception of motion.

METHODS Five patients (two males and three females) with ophthalmoplegia were included in the study. The average age was 44 years (range 30–69 years). The aetiology of ophthalmoplegia was myasthenia gravis (MG; n=2), chronic progressive external ophthalmoplegia (CPEO; n=2), and chronic idiopathic orbital inflammation. Visual motion detection thresholds were assessed using horizontal and vertical gratings (spatial frequency) set at thresholds for visibility. The grating was then accelerated at 0.09 deg/s2. The subject's task was to detect the drift direction of the stimulus.

RESULTS Visual motion detection thresholds were raised to a mean of 0.434 deg/s (SD 0.09) (mean normal value 0.287 deg/s (SD 0.08)) for horizontal motion; and to a mean of 0.425 deg/s (SD 0.1) (mean normal value 0.252 deg/s (SD 0.08)) for vertical motion. The difference in values for both horizontal and vertical motion detection were statistically significant when compared with age matched controls; p <0.023 for horizontal motion and p<0.07 for vertical motion (two tailedt test).

CONCLUSION Abnormally raised visual motion thresholds were found in patients with ophthalmoplegia. This may represent a centrally mediated adaptive mechanism to ignore excessive retinal slip and thus avoid oscillopsia during head movements.

Footnotes

  • ↵Current address: Academic Department of Neuro-otology, Division of Neuroscience, Imperial College, Charing Cross Hospital, London, UK

  • ↵Current address: College of Optometry, Nova Southeastern University, 3200 South University Drive, Fort Lauderdale, FL 33328–2018, USA

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