Eyes-On Glasses let nurses see patients' veins through their skin:
"The glasses can be worn over existing eyewear, and incorporate "multi-spectral 3D imaging" (multiple spectra of projected light) to make veins show up when viewed via the glasses' dual cameras. Users see the patient's skin as it really is through the glasses' clear lens, but with an image of the veins as processed by the cameras overlaid on top."
Eyes-On Glasses should be commercially available to medical clients as of the first quarter of next year. More information is available in the video."
Given the extensive capability advertised in the video and the target market, I suspect they'll be expensive, but if you have hard to find veins, you might soon be shopping around to find a place that uses these to reduce the discomfort/pain associated with regular blood tests...
If the company decides to release a basic model without the network connectivity and audio conferencing facilities, I could see these really taking off. Then all you have to hope for is that you don't strike a nurse or phlebotomist that is convinced that their experience is more than a match for your disappearing veins!