Evaluating the lateral resolution of the adaptive optics scanning laser ophthalmoscope

We present a statistical assessment of the lateral resolution of the adaptive optics scanning laser ophthalmoscope (AOSLO). We adopt a 2-D Gaussian function to approximate the AOSLO point spread function (PSF), which is dominated by the residual wavefront aberration and characterized by the Strehl ratio. Thus, we derive the lateral resolution in the presence of residual wave aberrations, which is inversely proportional to square root of the Strehl ratio. The modeling, while not sufficient in describing the fine structure of the real PSF, demonstrates good conformance to the lateral cross section of the real PSF. With this model, the lateral resolution of our current AOSLO was computed to be 1.65 to 2.33 microm, which agreed well with the actual result. We also reveal the relationships among the lateral resolution and other three measures of the AOSLO imaging property including the Strehl ratio, the PSF, and the root mean square (rms) of wavefront aberration.