Figure 1.

Results of raytrace analysis to determine Strehl ratio throughout a 3D region of interest (ROI) in the tissue beneath the lens. (a) and (d) show the simulation configurations; (b), (c), (e) and (f) are contour plots of Strehl ratio over an axial cross section of a region of interest that is 450 μm in diameter laterally and 200 μm deep. The black line shows the $S=0.8$ contour. The hemisphere lens shown in (a) is aplanatic at the glass-tissue interface (no coma or spherical aberration). b) With no correction of spherical aberration with depth, the performance falls off as the focal point is positioned deeper beneath the surface. c) With correction of spherical aberration with depth, the performance can be extended throughout the 200 μm thickness used for this simulation. For the hemisphere lens, the lateral field of view of both (b) and (c) is limited by uncorrected astigmatism. The hyperhemisphere lens shown in (d) is slightly thinner than $R(1+1∕n_g)$, causing the depth of best correction to occur at 100 μm into the tissue. e) With no active control over spherical aberration, the performance decays axially as well as laterally. f) With correction of spherical aberration with depth, performance on-axis can be extended throughout the 200 μm thickness used for this simulation. At the “natural” depth for the hyperhemisphere, the lens is approximately anastigmatic, with a very wide lateral field of view. Shallower and deeper, the aberrations grow with contribution from both coma and astigmatism contributing to reduced Strehl ratio.