Any Dienstglas collectors here, strange eyecups?

[Larboard]

Picked up these pretty much straight from the Vet Dienstglas, DDX coded for Voigtlander. The eyecups are unusual, anyone seen similar eyecups before? They are flat, maybe for eyeglass wearers? I have never actually seen these on a pair of Diensglas before.

[Flak bunker]

Very unusual,I have seen them once before but on a different binocular,there is a couple of opinions first some say they were made for use with a gas mask second is for spectacle wearers,hope this helps,

[Larboard]

Danke, Flak bunker ;-)

[Dean]

Interesting..I wonder if they came standard from the factory this way or was there an option to get these extra fittings to screw on when needed..hmm. Great question!
Nice pair of binos, by the way
Dean.

[Dean]

Here are my ddx/Voigtlander binoculars with the standard fittings for comparrison .

Also, I forgot to say,"Welcome!" To our fine forum
Dean.

[Flak bunker]

Not sure dean,I have a couple of examples adapted in the field by troops filing the eye cups flat