0_6772 Digital holographic microscopy is a quantitative technique that enables computational reconstruction of the entire wavefield from an interference pattern, known as a hologram, between the object and reference wave captured by an imaging sensor. In reflection mode, the object wave is reflected from a sample and interfered with the reference wave at an oblique angle producing a so-called off-axis hologram. By applying computational filtering in the Fourier space, the acquired off-axis hologram is reconstructed into the amplitude and phase of the object wave. The phase of the object wave carries information about the surface topography of the sample at a resolution on the scale of a one-hundredth of a wavelength of light. Since digital holographic microscopy in reflection mode is inherently a snapshot technique and limited only by the camera framerate, it is highly suitable for studying dynamic changes in the surface topography of media such as liquid crystals. In this study, we employed digital holographic microscopy in reflection mode to investigate the behavior of a nematic liquid crystal on micropatterned substrates under various conditions. Micropatterned substrates are based on Si wafers comprising pillars of circular, square, or triangular cross-sections distributed in a square or hexagonal lattice with characteristic dimensions in the order of a few tens of micrometers. The regular arrangement of pillars provides a controlled approach in creating and positioning topological defects in a thin layer of a nematic liquid crystal. While polarized light microscopy is the most commonly utilized technique to characterize the resulting in-plane director field of the nematic liquid crystal, and lateral position and winding number of the topological defects, digital holographic microscopy in reflection mode provides an additional insight related to the out-of-plane director field configuration and topography of the top nematic liquid crystal interface. By leveraging the advantages of digital holographic microscopy, we investigate the formation and dynamics of topological defects and their influence on the topography of the top interface between the nematic liquid crystal and media such as air, water, or surface treated glass. We study how the configuration of the topological defects and the top interface topography depend on the shape and arrangement of the micropatterned pillars, the substrate surface functionalization which imposes planar or homeotropic anchoring of the liquid crystal molecules, and the thickness of the nematic liquid crystal layer. Finally, we present the effect of the thermal phase transition from the nematic to smectic A phase on the top interface topography.