Specific embodiments of the invention are directed to improved
phacoemulsification procedures involving the use of processed non-visual three-dimensional data (i.e.
diagnostic scan data) to provide a surgeon with additional guidance (i.e. more than that generally obtained from
visual observation of the working area) concerning the distance separating a working end of a
phacoemulsification instrument and the posterior portion of the
capsule of the eye during
surgical procedures involving the removal of the crystalline lens of an eye (e.g. a cataract
removal procedure). Such separation (i.e. distance or gap) information may be used to aid the surgeon in
cutting or scoring the lens to a desired depth while minimizing the risk of penetrating the posterior portion of the
capsule with the working end of the instrument. Some embodiments provide for the visual and / or auditory conveyance of distance information to the surgeon wherein visual information may be conveyed by overlaying it with real visual images of actual surface features viewed by the surgeon. Additional embodiments provide for overlaying visual representations of selected three-dimensional structure information (e.g. depths of troughs
cut into the lens) with the real surface feature images viewed by the surgeon.