Hello :-)
What eyepiece is it? (image, link?)
While the barrel diameter is standardized, the rest of the eyepiece isn't, really. So it's not one size fits all. But yes, some are available (Meade, microscope eye guards, Vernonscope...)
You can also whip something up with foam pipe insulation from the hardware store.
Keep in mind that for $25 (Aliexpress, ebay) to $36 (Amazon) you can get a 66° wide-angle & long eye-relief eyepiece. Or for as little as $8 you can get a no-name 10mm Plössl with an eye-cup.