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Why have microsaccades become larger? Investigating eye deformations and detection algorithms

Nyström, Marcus LU ; Witzner Hansen, Dan; Andersson, Richard LU and Hooge, Ignace (2016) In Vision Research 118. p.17-24
Abstract (Swedish)
Abstract in Undetermined

The reported size of microsaccades is considerably larger today compared to the initial era of microsaccade studies during the 1950s and 1960s. We investigate whether this increase in size is related to the fact that the eye-trackers of today measure different ocular structures than the older techniques, and that the movements of these structures may differ during a microsaccade. In addition, we explore the impact such differences have on subsequent analyzes of the eye-tracker signals. In Experiment I, the movement of the pupil as well as the first and fourth Purkinje reflections were extracted from series of eye images recorded during a fixation task. Results show that the different ocular... (More)
Abstract in Undetermined

The reported size of microsaccades is considerably larger today compared to the initial era of microsaccade studies during the 1950s and 1960s. We investigate whether this increase in size is related to the fact that the eye-trackers of today measure different ocular structures than the older techniques, and that the movements of these structures may differ during a microsaccade. In addition, we explore the impact such differences have on subsequent analyzes of the eye-tracker signals. In Experiment I, the movement of the pupil as well as the first and fourth Purkinje reflections were extracted from series of eye images recorded during a fixation task. Results show that the different ocular structures produce different microsaccade signatures. In Experiment II, we found that microsaccade amplitudes computed with a common detection algorithm were larger compared to those reported by two human experts. The main reason was that the overshoots were not systematically detected by the algorithm and therefore not accurately accounted for. We conclude that one reason to why the reported size of microsaccades has increased is due to the larger overshoots produced by the modern pupil-based eye-trackers compared to the systems used in the classical studies, in combination with the lack of a systematic algorithmic treatment of the overshoot. We hope that awareness of these discrepancies in microsaccade dynamics across eye structures will lead to more generally accepted definitions of microsaccades. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Vision Research
volume
118
pages
17 - 24
publisher
Elsevier
external identifiers
  • pmid:25481631
  • wos:000368968600003
  • scopus:84953411357
ISSN
1878-5646
DOI
10.1016/j.visres.2014.11.007
language
English
LU publication?
yes
id
2b80a60e-ced6-481a-ade3-a2bf4ccc9bb8 (old id 4856719)
date added to LUP
2014-12-04 11:02:43
date last changed
2017-10-08 03:21:03
@article{2b80a60e-ced6-481a-ade3-a2bf4ccc9bb8,
  abstract     = {<b>Abstract in Undetermined</b><br/><br>
The reported size of microsaccades is considerably larger today compared to the initial era of microsaccade studies during the 1950s and 1960s. We investigate whether this increase in size is related to the fact that the eye-trackers of today measure different ocular structures than the older techniques, and that the movements of these structures may differ during a microsaccade. In addition, we explore the impact such differences have on subsequent analyzes of the eye-tracker signals. In Experiment I, the movement of the pupil as well as the first and fourth Purkinje reflections were extracted from series of eye images recorded during a fixation task. Results show that the different ocular structures produce different microsaccade signatures. In Experiment II, we found that microsaccade amplitudes computed with a common detection algorithm were larger compared to those reported by two human experts. The main reason was that the overshoots were not systematically detected by the algorithm and therefore not accurately accounted for. We conclude that one reason to why the reported size of microsaccades has increased is due to the larger overshoots produced by the modern pupil-based eye-trackers compared to the systems used in the classical studies, in combination with the lack of a systematic algorithmic treatment of the overshoot. We hope that awareness of these discrepancies in microsaccade dynamics across eye structures will lead to more generally accepted definitions of microsaccades.},
  author       = {Nyström, Marcus and Witzner Hansen, Dan and Andersson, Richard and Hooge, Ignace},
  issn         = {1878-5646},
  language     = {eng},
  pages        = {17--24},
  publisher    = {Elsevier},
  series       = {Vision Research},
  title        = {Why have microsaccades become larger? Investigating eye deformations and detection algorithms},
  url          = {http://dx.doi.org/10.1016/j.visres.2014.11.007},
  volume       = {118},
  year         = {2016},
}