An ocular device for a surgical instrument, the surgical instrument having an optical window frame and an optical assembly arranged in an interior space of the surgical instrument, the ocular device including: an ocular window separated from the optical assembly by a space； a holder configured to be connected to the ocular window frame； and at least one elastic element, wherein in a connected state, the at least one elastic element transmits a clamping force from the holder to bias the ocular window towards the space.
