Detection of foveation windows and analysis of foveation sequences in congenital nystagmus

Giulio Pasquariello, Mario Cesarelli, Paolo Bifulco, Antonio Fratini, Antonio La Gatta, Domenico Boccuzzi

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Congenital nystagmus (CN) is an ocular-motor disorder characterised by involuntary, conjugated ocular oscillations, that can arise since the first months of life. Pathogenesis of congenital nystagmus is still under investigation. In general, CN patients show a considerable decrease of their visual acuity: image fixation on the retina is disturbed by nystagmus continuous oscillations, mainly horizontal. However, image stabilisation is still achieved during the short periods in which eye velocity slows down while the target image is placed onto the fovea (called foveation intervals). To quantify the extent of nystagmus, eye movement recording are routinely employed, allowing physicians to extract and analyse nystagmus main features such as shape, amplitude and frequency. Using eye movement recording, it is also possible to compute estimated visual acuity predictors: analytical functions which estimates expected visual acuity using signal features such as foveation time and foveation position variability. Use of those functions add information to typical visual acuity measurement (e.g. Landolt C test) and could be a support for therapy planning or monitoring. This study focus on robust detection of CN patients' foveations. Specifically, it proposes a method to recognize the exact signal tracts in which a subject foveates, This paper also analyses foveation sequences. About 50 eyemovement recordings, either infrared-oculographic or electrooculographic, from different CN subjects were acquired. Results suggest that an exponential interpolation for the slow phases of nystagmus could improve foveation time computing and reduce influence of breaking saccades and data noise. Moreover a concise description of foveation sequence variability can be achieved using non-fitting splines.

Original languageEnglish
Title of host publicationIFMBE Proceedings
Pages364-367
Number of pages4
Volume22
DOIs
Publication statusPublished - 2008
Event4th European Conference of the International Federation for Medical and Biological Engineering, ECIFMBE 2008 - Antwerp, Belgium
Duration: Nov 23 2008Nov 27 2008

Other

Other4th European Conference of the International Federation for Medical and Biological Engineering, ECIFMBE 2008
CountryBelgium
CityAntwerp
Period11/23/0811/27/08

Keywords

  • Congenital nystagmus
  • Eye movement signal processing
  • Foveation
  • Interpolation

ASJC Scopus subject areas

  • Bioengineering
  • Biomedical Engineering

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  • Cite this

    Pasquariello, G., Cesarelli, M., Bifulco, P., Fratini, A., La Gatta, A., & Boccuzzi, D. (2008). Detection of foveation windows and analysis of foveation sequences in congenital nystagmus. In IFMBE Proceedings (Vol. 22, pp. 364-367) https://doi.org/10.1007/978-3-540-89208-3_86