Tried to respond to your YMB post about KOPN FOV. Your initial message disappeared, so I tried to post my response as a new message, but the site deleted it 4 times, so I gave up. Here it is...
@TrashcanMan KOPN's previously announced pancake lenses (P95 w/ 95 deg FOV) are probably a better comparison to EMAN's 4K application, since KOPN's new lenses (P80) open up the eye box and eye relief to accommodate wearing glasses. Note that KOPN is quoting FOV based on diagonal measurement, not horizontal/vertical. EMAN 4K discussions focus on 4K pixels in each direction, 100 deg FOV, and 40 pixels/deg, so they are talking about H/V FOV, not diagonal FOV. 100 deg H/V FOV equates to 120 deg diagonal FOV. OTOH, KOPN's 95 deg diagonal FOV equates to 75 deg H/V FOV, and taking 2560 pixels H & V resolution, that works out to 34 pixels/deg. So the 4K EMAN application has both larger FOV and higher pixel density. Attached a link below that you might find useful for computing/comparing FOV.
http://vrguy.blogspot.com/2013/04/converting-diagonal-field-of-view-and.html