Eye Movement Lab

Equipment

SMI iView X

We have a number of SMI video-based eye trackers.

Our main system is an iView X HiSpeed, which allows us to make accurate, two dimensional, monocular or binocular eye movement recordings at up to 1250 Hz. We utilise SMI's proprietary software for recording and analysis and are maintain our own software for extra analysis capabilities.
This system is used in conjunction with a fast DLP projector to present large images, and was purchased in 2007 with a grant from the NZ Lotteries Commision.
Our secondary HiSpeed system (from 2005) runs at 240 Hz (monocular) or 350 Hz (binocular). This was obtained with the kind assistance of the Canterbury Medical Research Foundation and Holcim (New Zealand) Ltd.
The iView X HED is a helmet mounted system which allows the particpant to be fully mobile while their gaze position is recorded on top of a scene video.
We also use our SMI eye tracking PCs in concert with an Avotec fibre optic system to allow eye tracking within the bore of a General Electric 3T MRI machine.

Skalar IRIS

The IRIS is an infrared limbus tracker produced by Skalar Medical. A lightweight helmet suspends a sensor in front of each eye. It is a one-dimensional system, allowing either vertical or horizontal movements to be measured in a given eye. We generally record at 200 Hz, sufficiently fast to examine saccades and fast phases of nystagmus.

A row of infrared LEDs above the pupil shines light upon the cornea. The reflected light is measured by the row of sensors below the pupil. The difference between the amount of light reflected by the white sclera on each side of the iris is proportional to eye position. Eye position, eye velocity, and stimulus position are stored and analysed using EMMA (Eye Movement Measuring and analysis), custom software developed by the Department of Medical Physics and Bioengineering at Christchurch Hospital .

Flying spot laser scanner

This unique device was developed as a collaboration between the Department of Electrical and Electronic Engineering at the University of Canterbury and the Department of Medical Physics and Bioengineering at Christchurch Hospital. It allows simultaneous monocular recordings of 3D (horizontal, vertical, and torsional) eye movements.

A flying spot laser scans the eye horizontally and vertically to locate the position of the pupil centre. It then performs a circular scan around the iris to allow torsional rotation to be calculated by measuring the shifts of iris striations between successive scans.

The laser scanner is described in several papers listed on the publications page. The system is no longer being actively developed.