We present results of imaging experiments using digital interference holography (DIH). Calibration experiments using a resolution target demonstrate an improvement of signal-to-noise ratio (SNR) with increasing number of holograms consistent with theoretical prediction. Imaging experiments on retinal tissue reveal the topography of blood vessels as well as the optical thickness profile of the retinal layer. The SNR of tissue images is comparable to that of the resolution target, implying that the imaging system is operating close to theoretical optimum.