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Saccades
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- Saccades (EyeLink I, II, 1000, 1000 Plus, Portable Duo):
SSACC <eye > <stime>
ESACC <eye > <stime> <etime > <dur> <sxp > <syp> <exp > <eyp> <ampl > <pv >
ESACC <eye > <stime> <etime > <dur> <sxp > <syp> <exp > <eyp> <ampl > <pv > [<xr> <yr >]
- Saccades (EyeLink 3):
SSACC <eye> <stime> <hissx> <hissy> <hisex> <hisey> <hisax> <hisay> <eihsx> <eihsy> <eihex> <eihey> <eihax> <eihay> <hrsx> <hrsy> <hrsz> <hrex> <hrey> <hrez> <hrax> <hray> <hraz> <hpsx> <hpsy> <hpsz> <hpex> <hpey> <hpez> <hpax> <hpay> <hpaz>
ESACC <eye> <stime> <etime> <dur> <sxp> <syp> <exp> <eyp> <ampl> <pv> [<xr> <yr>] <hissx> <hissy> <hisex> <hisey> <hisax> <hisay> <eihsx> <eihsy> <eihex> <eihey> <eihax> <eihay> <hrsx> <hrsy> <hrsz> <hrex> <hrey> <hrez> <hrax> <hray> <hraz> <hpsx> <hpsy> <hpsz> <hpex> <hpey> <hpez> <hpax> <hpay> <hpaz>
Note that
- <xr> <yr> are optional output enabled by passing in the -res switch when running the conversion from the command prompt or enable the "Output Resolution Data" option from "Preferences"..
- For EyeLink 3, the head tracking data (<hrsx> <hrsy> <hrsz> <hrex> <hrey> <hrez> <hrax> <hray> <hraz> <hpsx> <hpsy> <hpsz> <hpex> <hpey> <hpez> <hpax> <hpay> <hpaz>) can be disabled by passing in the "-nht" switch when running the conversion from the command prompt or enable the "EyeLink 3 -> Blocking Head Tracking Output" option from "Preferences".
- For EyeLink 3, the extended eye/head position data (<hissx> <hissy> <hisex> <hisey> <hisax> <hisay> <eihsx> <eihsy> <eihex> <eihey> <eihax> <eihay>) can be disabled by passing in the "-ned" switch when running the conversion from the command prompt or enable the "EyeLink 3 -> Blocking Extended Eye Position" option from "Preferences".
The start of saccades are reported with a SSACC line, which can be eliminated by blocking the start event. The <eye> is "L" or "R", indicating the eye's data that produced the event.
The end of and summary data on the saccade are reported with the ESACC line. This reports the time of the first and last sample in the saccade, and computes its duration in milliseconds. The X and Y eye position at the start and end of the saccade (<sxp>, <syp>, <exp>, <eyp>) are listed. The total visual angle covered in the saccade is reported by <ampl>, which can be divided by (<dur>/1000) to obtain the average velocity. Peak velocity is given by <pv>. Optionally, the eye-position angular resolution (in units per visual degree) are given as well.
All samples that are within the saccade will be listed between the SSACC and ESACC events for each eye, simplifying data analysis.
Data notations:
| Field | Content |
| <eye > | which eye caused event ("L" or "R") |
| <time > | timestamp in milliseconds |
| <stime > | timestamp of first sample in milliseconds |
| <etime > | timestamp of last sample in milliseconds |
| <dur > | duration in milliseconds |
| <axp > <ayp > | average X and Y position |
| <sxp > <syp > | start X and Y position data |
| <exp > <eyp > | end X and Y position data |
| <aps > | average pupil size (area or diameter) |
| <av > <pv > | average, peak velocity (degrees/sec) |
| <ampl > | saccadic amplitude (degrees) |
| <xr > <yr > | X and Y resolution (position units/degree) |
| <hissx > <hissy > | X, Y head position in screen pixel coordinates when the event starts |
| <hisex > <hisey > | X, Y head position in screen pixel coordinates when the event ends |
| <hisax > <hisay > | Average X, Y head position in screen pixel coordinates |
| <eihsx > <eihsy > | Participant's eye pose in relation to the head, without head-movement contribution, represented as a gaze point on the screen (X, Y in screen pixel coordinates) when the event starts |
| <eihex > <eihey > | Participant's eye pose in relation to the head, without head-movement contribution, represented as a gaze point on the screen (X, Y in screen pixel coordinates) when the event ends |
| <eihax > <eihay > | Average rotation of the eye within the head along the X- and Y-axis (in screen pixel coordinates) |
| <hrsx > <hrsy > <hrsz > | Rotation angle (in degrees) of the head around the X-axis (pitch), the Y-axis (yaw), and the Z-axis (roll) when the event starts. |
| <hrex > <hrey > <hrez > | Rotation angle (in degrees) of the head around the X-axis (pitch), the Y-axis (yaw), and the Z-axis (roll) when the event ends. |
| <hrax > <hray > <hraz > | Average rotation angle (in degrees) of the head around the X-axis (pitch), the Y-axis (yaw), and the Z-axis (roll). |
| <hpsx > <hpsy > <hpsz > | Translational movements along the X, Y, and Z axes when the event starts. |
| <hpex > <hpey > <hpez > | Translational movements along the X, Y, and Z axes when the event ends. |
| <hpax > <hpay > <hpaz > | Average translational movements along the X, Y, and Z axes. |