Advanced Dual-Purkinje-Image Eyetrackers

The FOURWARD TECHNOLOGIES, INC. Dual-Purkinje-Image (DPI)Eyetracker is a solidly engineered product which provides a dependable, accurate, and proven eye movement tracking device.

The DPI Eyetracker was developed by SRI International, and SRI has appointed FOURWARD TECHNOLOGIES, INC. as their exclusive licensee for the Eyetracker Technology. It determines the direction of gaze over a large, two-dimensional visual field with great accuracy and without attachments to the eye. This instrument has been used for over 20 years in various configurations, and some of these original instruments are still being used today.

The Dual-Purkinje-Image Eyetracker operates with infrared light and does not interfere with normal vision. Troublesome artifacts introduced by translational and axial head and eye movements are automatically minimized.

The DPI Eyetracker can utilize a simple chin and forehead rest to provide adequate head stabilization for many applications.

To produce a three-dimensional Eyetracker, an optometer option can be incorporated to allow a continuous measure of accommodation, as well as eye movements.

Today, the DPI Eyetracker is used successfully in a variety of vision and research projects in commercial, university and government laboratories around the world. Due to its high accuracy, resolution, response time and convenience, the DPI Eyetracker finds itself the central tool in many unique research applications.

Options available:

Infrared Optometer

The Optometer is a real-time +/- 10 diopter optometer that attaches to the Fourward Eyetracker and tracks changes in accommodation while the Eyetracker tracks in the x/y axes. The Optometer can be attached to an existing Eyetracker or be provided with new units. The optometer displays continuous accommodation changes on a front-panel meter and an additional analog output BNC. Calibration is provided by the end user.

Stimulus Deflector

The Stimulus Deflector, also called the Stabilizer, is an option that allows the horizontal and vertical rotational outputs of the Eyetracker to be fed back to a pair of x/y galvanometers that are in the optical path. With proper adjustment the "real world" fixation targets can be stabilized at the retina. There is also another option offered to the stabilizer that allows a focus stimulus in the "z" axis for a 3"D system. With the Stimulus Deflector you also have control over spherical correction (focus) and provision for the placement of trial lenses (astigmatic correction).

Scotoma Device

The Scotoma Device is an attachment to the stimulus deflector which allows a scotoma image of any shape to be stabilized on the retina, while the "real world" remains unstabilized. These "scotomas" are created on a glass plate that blocks a portion of the viewing area and simulates retinal pathologies.

Fundus Illumination and Measuring Instrument (FIMI)

The Fundus Illumination and Measuring Instrument (FIMI) option allows real-time binocular viewing of the retina by a white-light source, while a stabilized low-power He-Ne pilot laser beam is stabilized by the operator on the retina.