To Occlude or not to Occlude?

A question came up on the Natalia Gameplay Youtube video a couple of days ago:

I have a question? since it doesn't cover the whole eye area can you be distracted by light and stuff coming through the sides. i love the ideal of a headset and cameras and stuff in the front of it to track hand movement but i just don't like the idea of there an opening on the sides ?

This brings up a nice opportunity to speak about occlusion (the blocking of light) in goggles. At Sensics, we have done it both ways: some products block pretty much all external light from coming into the goggle, making the user entirely focused on the image displayed inside, and some products allow some peripheral vision. For instance, two products that can be configured for identical resolution and field of view are:

piSight - not occluded

xSight - fully occluded

the xSight is based on a ski-goggle design with a mask that touches the face all around the edge of the goggle. The piSight, on the other hand, hangs the optics in front of the eyes using an over-the-head rail structure which is very comfortable (in spite of looking like a torture device).

What are the advantages of an occluded design (such as the xSight)?

• Allows the user to completely focus on the displayed image
• Increases display contrast by blocking outside light
• Enhances the sense of immersion by blocking outside distractions

What are the advantages of a non-occluded design (such as the piSight)?

• Better orientation in the physical space. Goggle allows peeking sideways or looking down to the floor or to find a keyboard underneath the goggle. If the user of the goggles is expected to substantially move around in a room, a non-occluded design will feel safer to the user.
• If coordination with additional people is needed, easier to see where these people are and view their behavior and gestures. For instance, in an infantry training application, most goggles used are not occluded.
• Easier access to vicinity of the eyes if there is a need to adjust devices such as built-in eye tracker
• Easier to wear glasses. Most often, the difficulty in wearing glasses with goggles is not so much the eye relief (distance from the optics to the eyes) but rather the frame of the eyeglasses interfering with the enclosure of the goggles. A non-occluded design goes a long way to alleviate this problem.

In some instances, we tried to have the best of both worlds: a non-occluded design but with detachable blinders that allow to increase then occlusion when required.

In short - there is no right answer. Goggle design is about tradeoffs and the right choice depends on the requirements and applications.