A research survey organizes the smart-glasses field around seven interdependent foundational capabilities and proposes an L0-L5 framework spanning capture, reactive perception, contextual assistance, persistent state, governed action, and embodied coupling. The work systematizes evaluation through nine application scenarios, a nine-dimensional deployment framework, and a claim-conditioned evaluation protocol progressing from controlled measurement to field validation. Rather than isolated model performance, the framework centers on whether a complete system can sustain a reliable, temporally valid, correctable, and governable perception-state-interaction-action loop.
