A portable MEMS-based scanning laser ophthalmoscope (MSLO). In one example the MSLO includes a laser illumination sub-assembly that generates a laser illumination beam, a two-dimensional MEMS scan mirror configured to receive and scan the laser illumination beam over at least a portion of the retina of an eye to be imaged, an optical system configured to direct the laser illumination beam from the scan mirror into the eye to illuminate the retina, and a detector sub-assembly configured to intercept optical radiation reflected from the eye to generate an image of the retina. The optical system includes a polarized beamsplitter positioned between the scan minor and the eye and configured to direct the laser illumination beam to into the eye and to direct the optical radiation reflected from the eye to the detector sub-assembly.