A wearable computing device reads near-invisible one- or two-dimensional barcodes having a size of 100 microns to one millimeter. The device includes a magnifying lens, a digital camera, a processor, program memory and a wireless communication module, all supported on a wearable device body. The wearable device body may be an eyeglass frame, a watch body or wristband, a headband or sweatband or a cap or other headgear, among other possibilities. Applications of the wearable computing device include unattended shopping in a physical retail store.