PLATO Visual Occlusion Spectacles

An animation showing the lenses of the PLATO occlusion spectacles opening and closing PLATO stands for “Portable Liquid crystal Apparatus for Tachistoscopic Occlusion”. The following is a list of some of the properties of  PLATO:

            • Unprecedented control over visual input to subjects’ eyes.
            • Lenses switch from occluding (light scattering) to transparent state in approx 4 ms.
            • 80% of incident light is transmitted in transparent state.
            • Transition from clear (‘shutter open’) to occluding (‘shutter closed’) in about 3 ms.
            • No problems of light-dark adaptation, because significant incident light in both states.
            • Each lens independently controlled by separate TTL voltage signals.

         Click here for more general information about the PLATO spectacles, and here for specific details of the physical and optical characteristics of the PLATO lenses.

ToTaL Control System (USB)

A flexible means of generating TTL signals, either manually or externally triggered. Three modes of operation are possible:

  • Continually tethered, via USB, to a host computer.
  • In (untethered) stand-alone mode.
  • With remote wireless receiver (in tethered or untethered mode).

The ToTaL Control System is not limited only to controlling the PLATO spectacles, but can also be used as a generic programmable dual channel TTL pulse generator. Click here for more details.

Parallel Port + ToTaLcontrol Software (Older Method)

The ToTaLcontrol software is our older method of generating TTL signals for the PLATO spectacles. It differs from the newer ToTaL Control System by relying on the computer’s parallel port for generating TTL signals and for receiving external triggers.   Anyone with a Windows computer (up to XP or 2000) with a parallel port can still use the older  ToTaLcontrol software. Click here for more details.


Please note that it is not absolutely necessary for users of the PLATO visual occlusion spectacles to acquire our TTL pulse generation software.  Any other method of generating TTL voltage levels will work perfectly well.


If you would like to discuss how our products might be applied to your research application, and to find out about pricing and availability, please contact Dr. Paul Milgram.

Our Terms and Conditions of purchase may be viewed here.