coefficients corresponded various forms of aberration that are encountered in optical systems with circular pupils iterating through the polynomial coefficients thus provides a significantly reduced set of choices after the optimized zernike polynomial coefficients are obtained then at process block 100 optional additional fine adjustment of the mirrors may be had using conventional hill climb techniques at process block 102 the focal plane 26 may be scanned with these settings making an assumption of constant aberration at a given depth or with the zernike coefficients held constant and fine adjustments allowed or with a repetition of process block 98 and process block 100 at each scan point after the focal plane 26 is scanned at process block 104 the focal spot may be parked at a greater depth e g at a deeper focal plane 26 and this process repeated preferably for each focal plane 26 the process of block 98 begins with the coefficients previously established at the preceding focal plane 26 as indicated by process block 106 further reducing the amount of iteration required similarly it may be possible to pre characterize the aberration at various points in the tissue and then to use those aberrations samples as a starter point for limited iteration on the tissue at a later time referring now to fig9 the reflection diffraction element 58.