The optical setup of the measurement system is depicted in Fig. 1. As light source, a superluminescent diode (Superlum, Carrigtwohill, Cork, Ireland) with a central wavelength of 841 nm and a full width at half maximum bandwidth of 50 nm was used. This resulted in an axial resolution in air of . A beamsplitter with a splitting ratio of 50:50 divided the light coming from the source into the sample and reference arms. The free-space pathway of the reference arm contained a variable neutral density (ND) filter and a pair of prisms for balancing dispersion due to the optic components in the sample arm. In the sample arm, light was collimated by means of a fiber collimator, passed two galvanometric mirrors (GVS002; Thorlabs GmbH, Dachau/Munich, Germany) for scanning in two dimensions, and illuminated the eye via the lenses L1 and L2, where L2 is the ophthalmic lens of the retinal vessel analyzer. The interference spectrum returning from the interferometer was directed onto a transmission grating with lines per mm (Wasatch Photonics, Logan, Utah) using a collimator with a focal length (OZ Optics, Ottawa, Canada). The dispersed light emerging from the transmissive grating was imaged onto a CCD camera (Atmel AVIIVA M2 CL2014, Aviva, Essex, UK) with a pixel size of by means of an achromatic lens ().