a surgical device for altering the curvature of an eye includes a base which carries a transparent insert , a drive device , a knife edge coupled to the drive device and movable to a plane immediately adjacent the under surface of the transparent insert . the transparent insert includes a face having a surface portion shaped according to a predetermined correction . the base further includes a suction ring which forms a vacuum chamber with the eye . the suction ring is placed against the eye . application of vacuum results in the cornea of the eye being urged into engagement with the shaped surface portion . actuation of the drive device moves the knife edge whereby the cornea is cut . only the knife edge traverses the insert .