Purpose: To visualize the pre-corneal tear film with high resolution spectral domain optical coherence tomography, enabling quantification of tear film thickness in healthy subjects. Methods: A custom built spectral domain optical coherence tomography system comprising a broad band Ti:Sapphire laser operating at 800 nm and a high speed CCD camera with a read out rate of 47 kHz was used for measurement of pre-corneal tear film thickness. The system provides an axial resolution of 1.2 µm in tissue. A total of 26 healthy subjects were included in this study. Measurement was started immediately after blinking and averaged over ...