An apparatus for treating a biological tissue of a patient in situ
includes an optical fiber for guiding a coherent waveform of a selected
wavelength to a fiber tip. The wavelength is selected to have a low
absorption in water. The fiber tip is contained within a guide member
having a discharge bore to define an unobstructed light pathway. The
guide member is adapted to be slidable along a tissue surface in
atraumatic sliding engagement with the discharge bore opposing the
surface. The guide member is carried on an elongated flexible member.