Contact lens with stretchable distributed-feedback laser for intraocular pressure monitoring

Operating at a symmetry-protected bound state in the continuum at the Γ point, the device produces a narrow lasing line whose wavelength shifts directly with grating strain - a quantity not constrained by the spatial uncertainty principle. The DFB structure is fabricated by UV holographic lithography and transferred onto the lens by a simple float-off process, yielding a stretchable, transparent, polymer-compatible sensor that is intrinsically scalable.

Tested on a custom artificial eye model whose pressure-induced deformation is comparable in scale to that reported for the human eye, the sensor achieves a sensitivity of 0.027 nm/mmHg and a calibration residual of 1.2 mmHg under phantom conditions, a level relevant to tonometric monitoring, with substantial headroom currently limited mainly by auxiliary readout equipment.