We assume that you are referring to conjunctival nevus.
The procedure in which the eye nevus is removed is quite straightforward in most cases. It involves a local excision involving eye drop anaesthesia.
If the nevus is large, the eye surgeon may opt to do conjunctiva patch graft harvested from the under the eyelid or the other eye. The eye surgeon may elect to apply anti-scarring (Mitomycin C) agent to prevent post-op conjunctiva scarring.
It is important to avoid exposure to sunlight for the first two months.