Human spermatozoa having morphological anomalies as imaged by SNOM. (A) 3D SNOM topography of two tail spermatozoa: blue arrowhead indicates the end of midpiece, while red arrow indicates the end of post-acrosome area. (B) SNOM optical reflection and (C) transmission images. (D) 3D SNOM topography of a zoomed scan area of midpiece region together with SNOM reflection (E) and transmission (F) images. (G) 3D SNOM topography of a coiled sperm and corresponding SNOM optical reflection (H) and (I) transmission images.