A lens assembly for a drape for creating a barrier between a sterile field and an optical device having an objective lens, the drape includes a drape body sized to cover at least a portion of the optical device. The lens assembly comprises: a lens housing which is configured to attach to the drape body and to engage with the optical device to thereby mount the lens assembly to the optical device proximate the objective lens a lens cover holder removably attached to the lens housing and configured to rotate about a first axis and a transparent or substantially transparent lens cover attached to the lens cover holder to pivot about a second axis, the second axis being generally transverse with respect to the first axis.
