I use eye-piece adaptor came with TEMPA magnifier for EOS 350D,
(which has a square base and round female thread just like DK-22)
and attached Nikon DK-2 eyecup, which also hides eye sensor as
Minolta's (very old) eyecup does. You can add a diopter lens to this
eyecup when your eyesight is out of camera's adjustable range.

Note: This cup does not block the movement of movable screen.