The following supplemental videos are included with the PhD thesis titled, "A Universal Image-Based Autofocus Device for Video Microscopy: Application to Non-Invasive Imaging of the Conjunctival Microcirculation with Single-Cell Resolution". They provide visual demonstrations of the system’s operation and performance. S1: Conjunctival imaging with autofocus: Video of the conjunctival microcirculation with active autofocus, demonstrating live focus-holding during imaging (40 s). S2: Conjunctival imaging with autofocus (0.5×): Slow-motion video illustrating single-erythrocyte resolution and focus stability (33 s). S3: Conjunctival imaging with and without autofocus: Simultaneous side-by-side recording showing improvement in image stability and clarity (18 s). S4: Polymer sponge tensile test with and without autofocus: Side-by-side autofocus and fixed-focus views of a polymer sponge tensile test on a benchtop microscope, illustrating focus-holding and cross-platform generalization (25 s). S5: Perturbed circuit board with and without autofocus: Side-by-side autofocus and fixed-focus views of a printed-circuit board undergoing dynamic perturbation, demonstrating generalization across imaging targets (9 s). S6: Autofocus software interface: Screen recording of the autofocus software application, highlighting the depth-mapping and double-click-to-autofocus features (39 s).