Analysis of foveation sequences in congenital nystagmus

Giulio Pasquariello*, P. Bifulco, M. Cesarelli, M. Romano, A. Fratini

*Corresponding author for this work

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

Abstract

Congenital nystagmus (CN) is an ocular-motor disorder that appears at birth or during the first few months of life; it is characterised by involuntary, conjugated, bilateral to and fro ocular oscillations. Pathogenesis of congenital nystagmus is still unknown. Eye movement recording allow to extract and analyse nystagmus main features such as shape, amplitude and frequency; depending on the morphology of the oscillations nystagmus can be classified in different categories (pendular, jerk, horizontal unidirectional, bidirectional). In general, CN patient show a considerable decrease of the visual acuity: image fixation on the retina is disturbed by nystagmus continuous oscillations; however, image stabilisation is still achieved during the short foveation periods in which eye velocity slows down while the target image is placed onto the fovea. Visual acuity was found to be mainly dependent on foveation periods duration, but cycle-to-cycle foveation repeatability and reduction of retinal image velocities also contribute in increasing visual acuity. This study concentrate on cycle-to-cycle image position variation onto fovea, trying to characterise the sequences of foveation positions. Eye-movement (infrared oculographic or electro oculographic) recordings, relative to different gaze positions and belonging to more than 30 CN patients, were analysed. Preliminary results suggest that sequences of foveations show a cyclic pattern with a dominant frequency (around 0.3 Hz on average) much lower than that of the nystagmus (about 3.3 Hz on average). Sequences of foveations reveals an horizontal ocular swing of more than 2 degree on average, which can explain the low visual acuity of the CN patient. Current CN therapies, pharmacological treatment or surgery of the ocular muscles, mainly aim to increase the patient's visual acuity. Hence, it is fundamental to have an objective parameter (expected visual acuity) for therapy planning. The information about sequences of foveations can improve estimation of patient visual acuity.

Original languageEnglish
Title of host publication14th Nordic-Baltic Conference on Biomedical Engineering and Medical Physics
Subtitle of host publicationNBC 2008 16–20 June 2008 Riga, Latvia
EditorsAlexei Katashev, Yuri Dekhtyar, Janis Spigulis
Place of PublicationBerlin (DE)
PublisherSpringer
Pages303-306
Number of pages4
ISBN (Electronic)978-3-540-69367-3
ISBN (Print)978-3-540-69366-6
DOIs
Publication statusPublished - 2008
Event14th Nordic-Baltic Conference on Biomedical Engineering and Medical Physics - Riga, Latvia
Duration: 16 Jun 200820 Jun 2008

Publication series

NameIFMBE proceedings
PublisherSpringer
Volume20
ISSN (Print)1680-0737

Conference

Conference14th Nordic-Baltic Conference on Biomedical Engineering and Medical Physics
Abbreviated titleNBC 2008
CountryLatvia
CityRiga
Period16/06/0820/06/08

Fingerprint

Eye movements
Surgery
Muscle
Stabilization

Keywords

  • congenital nystagmus
  • eye movement signal processing
  • foveation
  • visual acuity

Cite this

Pasquariello, G., Bifulco, P., Cesarelli, M., Romano, M., & Fratini, A. (2008). Analysis of foveation sequences in congenital nystagmus. In A. Katashev, Y. Dekhtyar, & J. Spigulis (Eds.), 14th Nordic-Baltic Conference on Biomedical Engineering and Medical Physics: NBC 2008 16–20 June 2008 Riga, Latvia (pp. 303-306). (IFMBE proceedings; Vol. 20). Berlin (DE): Springer. https://doi.org/10.1007/978-3-540-69367-3-81
Pasquariello, Giulio ; Bifulco, P. ; Cesarelli, M. ; Romano, M. ; Fratini, A. / Analysis of foveation sequences in congenital nystagmus. 14th Nordic-Baltic Conference on Biomedical Engineering and Medical Physics: NBC 2008 16–20 June 2008 Riga, Latvia. editor / Alexei Katashev ; Yuri Dekhtyar ; Janis Spigulis. Berlin (DE) : Springer, 2008. pp. 303-306 (IFMBE proceedings).
@inproceedings{ed07a92c0b114ef695a6f9ec1b6d79ed,
title = "Analysis of foveation sequences in congenital nystagmus",
abstract = "Congenital nystagmus (CN) is an ocular-motor disorder that appears at birth or during the first few months of life; it is characterised by involuntary, conjugated, bilateral to and fro ocular oscillations. Pathogenesis of congenital nystagmus is still unknown. Eye movement recording allow to extract and analyse nystagmus main features such as shape, amplitude and frequency; depending on the morphology of the oscillations nystagmus can be classified in different categories (pendular, jerk, horizontal unidirectional, bidirectional). In general, CN patient show a considerable decrease of the visual acuity: image fixation on the retina is disturbed by nystagmus continuous oscillations; however, image stabilisation is still achieved during the short foveation periods in which eye velocity slows down while the target image is placed onto the fovea. Visual acuity was found to be mainly dependent on foveation periods duration, but cycle-to-cycle foveation repeatability and reduction of retinal image velocities also contribute in increasing visual acuity. This study concentrate on cycle-to-cycle image position variation onto fovea, trying to characterise the sequences of foveation positions. Eye-movement (infrared oculographic or electro oculographic) recordings, relative to different gaze positions and belonging to more than 30 CN patients, were analysed. Preliminary results suggest that sequences of foveations show a cyclic pattern with a dominant frequency (around 0.3 Hz on average) much lower than that of the nystagmus (about 3.3 Hz on average). Sequences of foveations reveals an horizontal ocular swing of more than 2 degree on average, which can explain the low visual acuity of the CN patient. Current CN therapies, pharmacological treatment or surgery of the ocular muscles, mainly aim to increase the patient's visual acuity. Hence, it is fundamental to have an objective parameter (expected visual acuity) for therapy planning. The information about sequences of foveations can improve estimation of patient visual acuity.",
keywords = "congenital nystagmus, eye movement signal processing, foveation, visual acuity",
author = "Giulio Pasquariello and P. Bifulco and M. Cesarelli and M. Romano and A. Fratini",
year = "2008",
doi = "10.1007/978-3-540-69367-3-81",
language = "English",
isbn = "978-3-540-69366-6",
series = "IFMBE proceedings",
publisher = "Springer",
pages = "303--306",
editor = "Alexei Katashev and Yuri Dekhtyar and Janis Spigulis",
booktitle = "14th Nordic-Baltic Conference on Biomedical Engineering and Medical Physics",
address = "Germany",

}

Pasquariello, G, Bifulco, P, Cesarelli, M, Romano, M & Fratini, A 2008, Analysis of foveation sequences in congenital nystagmus. in A Katashev, Y Dekhtyar & J Spigulis (eds), 14th Nordic-Baltic Conference on Biomedical Engineering and Medical Physics: NBC 2008 16–20 June 2008 Riga, Latvia. IFMBE proceedings, vol. 20, Springer, Berlin (DE), pp. 303-306, 14th Nordic-Baltic Conference on Biomedical Engineering and Medical Physics, Riga, Latvia, 16/06/08. https://doi.org/10.1007/978-3-540-69367-3-81

Analysis of foveation sequences in congenital nystagmus. / Pasquariello, Giulio; Bifulco, P.; Cesarelli, M.; Romano, M.; Fratini, A.

14th Nordic-Baltic Conference on Biomedical Engineering and Medical Physics: NBC 2008 16–20 June 2008 Riga, Latvia. ed. / Alexei Katashev; Yuri Dekhtyar; Janis Spigulis. Berlin (DE) : Springer, 2008. p. 303-306 (IFMBE proceedings; Vol. 20).

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

TY - GEN

T1 - Analysis of foveation sequences in congenital nystagmus

AU - Pasquariello, Giulio

AU - Bifulco, P.

AU - Cesarelli, M.

AU - Romano, M.

AU - Fratini, A.

PY - 2008

Y1 - 2008

N2 - Congenital nystagmus (CN) is an ocular-motor disorder that appears at birth or during the first few months of life; it is characterised by involuntary, conjugated, bilateral to and fro ocular oscillations. Pathogenesis of congenital nystagmus is still unknown. Eye movement recording allow to extract and analyse nystagmus main features such as shape, amplitude and frequency; depending on the morphology of the oscillations nystagmus can be classified in different categories (pendular, jerk, horizontal unidirectional, bidirectional). In general, CN patient show a considerable decrease of the visual acuity: image fixation on the retina is disturbed by nystagmus continuous oscillations; however, image stabilisation is still achieved during the short foveation periods in which eye velocity slows down while the target image is placed onto the fovea. Visual acuity was found to be mainly dependent on foveation periods duration, but cycle-to-cycle foveation repeatability and reduction of retinal image velocities also contribute in increasing visual acuity. This study concentrate on cycle-to-cycle image position variation onto fovea, trying to characterise the sequences of foveation positions. Eye-movement (infrared oculographic or electro oculographic) recordings, relative to different gaze positions and belonging to more than 30 CN patients, were analysed. Preliminary results suggest that sequences of foveations show a cyclic pattern with a dominant frequency (around 0.3 Hz on average) much lower than that of the nystagmus (about 3.3 Hz on average). Sequences of foveations reveals an horizontal ocular swing of more than 2 degree on average, which can explain the low visual acuity of the CN patient. Current CN therapies, pharmacological treatment or surgery of the ocular muscles, mainly aim to increase the patient's visual acuity. Hence, it is fundamental to have an objective parameter (expected visual acuity) for therapy planning. The information about sequences of foveations can improve estimation of patient visual acuity.

AB - Congenital nystagmus (CN) is an ocular-motor disorder that appears at birth or during the first few months of life; it is characterised by involuntary, conjugated, bilateral to and fro ocular oscillations. Pathogenesis of congenital nystagmus is still unknown. Eye movement recording allow to extract and analyse nystagmus main features such as shape, amplitude and frequency; depending on the morphology of the oscillations nystagmus can be classified in different categories (pendular, jerk, horizontal unidirectional, bidirectional). In general, CN patient show a considerable decrease of the visual acuity: image fixation on the retina is disturbed by nystagmus continuous oscillations; however, image stabilisation is still achieved during the short foveation periods in which eye velocity slows down while the target image is placed onto the fovea. Visual acuity was found to be mainly dependent on foveation periods duration, but cycle-to-cycle foveation repeatability and reduction of retinal image velocities also contribute in increasing visual acuity. This study concentrate on cycle-to-cycle image position variation onto fovea, trying to characterise the sequences of foveation positions. Eye-movement (infrared oculographic or electro oculographic) recordings, relative to different gaze positions and belonging to more than 30 CN patients, were analysed. Preliminary results suggest that sequences of foveations show a cyclic pattern with a dominant frequency (around 0.3 Hz on average) much lower than that of the nystagmus (about 3.3 Hz on average). Sequences of foveations reveals an horizontal ocular swing of more than 2 degree on average, which can explain the low visual acuity of the CN patient. Current CN therapies, pharmacological treatment or surgery of the ocular muscles, mainly aim to increase the patient's visual acuity. Hence, it is fundamental to have an objective parameter (expected visual acuity) for therapy planning. The information about sequences of foveations can improve estimation of patient visual acuity.

KW - congenital nystagmus

KW - eye movement signal processing

KW - foveation

KW - visual acuity

UR - http://www.scopus.com/inward/record.url?scp=70350687588&partnerID=8YFLogxK

UR - http://link.springer.com/chapter/10.1007/978-3-540-69367-3_81

U2 - 10.1007/978-3-540-69367-3-81

DO - 10.1007/978-3-540-69367-3-81

M3 - Conference contribution

AN - SCOPUS:70350687588

SN - 978-3-540-69366-6

T3 - IFMBE proceedings

SP - 303

EP - 306

BT - 14th Nordic-Baltic Conference on Biomedical Engineering and Medical Physics

A2 - Katashev, Alexei

A2 - Dekhtyar, Yuri

A2 - Spigulis, Janis

PB - Springer

CY - Berlin (DE)

ER -

Pasquariello G, Bifulco P, Cesarelli M, Romano M, Fratini A. Analysis of foveation sequences in congenital nystagmus. In Katashev A, Dekhtyar Y, Spigulis J, editors, 14th Nordic-Baltic Conference on Biomedical Engineering and Medical Physics: NBC 2008 16–20 June 2008 Riga, Latvia. Berlin (DE): Springer. 2008. p. 303-306. (IFMBE proceedings). https://doi.org/10.1007/978-3-540-69367-3-81