Natural viewing position and VR displays.

[budda]

Hi,

It appears that many head mounted displays are being designed to be mounted with a square-on position to the head.

It seems the central field of view is horizontal and level with the eye.

According to ergonomic principles, the natural resting view of the eyes is about 15 degrees down from the horizontal plane.

I am wondering if this principle is not followed with head mounted displays, then it could lead to eye fatigue or discomfort over long term use.

There may be both hardware and software workarounds for this situation, or it may turn out not to even be a problem.

However, some contingency in the design of head mounted displays should be made so the square-on mounting approach is not totally locked into the design from the beginning, and some design flexibility remains.


Thanks.

[zalo]

The infiniteye and wide5 have an angled setup... Is that what you mean?

[DarkAkuma]

The infiniteye and wide5 have an angled setup... Is that what you mean?

No. He seems to be talking about vertical slope, were as the infiteye angles the screens horizontally.

As for the OP, I believe what you mention is a non-issue as the HMD's I've seen here are designed to allow and expect your eyes to rotate in your eye sockets and allow you to focus were you want within the FOV. Also with head tracking, such a 15 degree difference would be compensated by the angle at which you hold your head.

[cybereality]

Maybe related, but I notice whenever I use HMDs I have the tendency to look down.

[geekmaster]

Notice next time you go out for a walk. Except when looking up to take your bearings (or enjoy the scenery), your gaze keeps the horizon high in your FoV, so that you can see in your lower FoV where you are about to place your feet. It is natural to avoid stepping on things that could trip you. We normally keep our gaze on the path ahead, not at the horizon. It would be good to keep the horizon near the top of our FoV when we hold our heads in a relaxed and balanced vertical posture. This is also how we are supposed to adjust our desktop monitors (center of screen well below horizon, and screen top no more than 15-degrees above true horizon), to minimize long-term neck strain.

In VR however, the VR horizon should be similar to the real horizon. The primary except to that rule is if you are using a recumbent walking simulation (as I am designing into my ExoHaptic EasyChair design), where you are actually laying back at an incline (greatly simplifying ODT-like self-directed and haptic feedback motion control and proprioceptive feedback).

[budda]

Hi,

There are different ways to make the central field of view look downward at 15 degrees.

1. Tilt the whole head mounted display down by 15 degrees.

2. Shift the lens and screen vertically so the line of sight is moved down by 15 degrees while keeping the lens and screen vertical.

3. Displace the image down by 15 degrees on the screen to relax the centreing of the eyes. This is done in the display software.

The relative ease of the fix is 3-2-1.

Also, if the 'centroid of eye viewing' in the game is too high vertically for too long, then maybe the game software could average down the point of view progressively as the game is played, to make it more comfortable for the eyes.


Thanks.

[WiredEarp]

Its an interesting point budda, but I don't really see this as being an issue at all unless the vertical FOV is small. With a decent vertical FOV, it would be little different to reality, and no-one complains about the real world being a strain to look ahead in.

[geekmaster]

Perhaps the best place to put the horizon (in software) is whatever causes the least long-term neck strain while looking 15-degrees below the horizon.