A goggles-like head-mounted device equipped with several non-invasive techniques for quantitative medical evaluation of the eye, skin, and brain is envisioned for monitoring the health of astronauts and cosmonauts during long-term space travel and exploration. Real-time non-invasive evaluation of the different structures within these organs will provide indices of the health of these organs, as well as the entire body. The techniques such as dynamic light scattering (for the early detection of cataracts to evaluate effects of cosmic radiation), corneal autofluorescence (to assess extracellular matrix biology (e.g., diabetes), optical polarization (of aqueous fluid to evaluate serum chemistry), laser Doppler velocimetry (of retinal, optic nerve, and choroidal blood flow to assess ocular as well as central nervous system blood flow), reflectometry/oximetry (for oxygen metabolism), optical coherence tomography (for retinal microstructure), and possibility scanning laser technology for intraocular imaging and scanning will be integrated into this compact device.