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Ophthalmologists might offer surgical procedures to fix presbyopia, such as corneal inlays, LASIK, photorefractive keratectomy and lens implants.

Lahav and colleagues’ solution was to shine a repetitive string of such pulses into a crystal of the photorefractive material strontium barium niobate, which responded to the power averaged over many pulses to create a self-guided beam.

It has been known for more than 20 years that self-guided light beams can be generated in photorefractive materials5.

The light from the sample is collected in a photorefractive crystal as a hologram with the use of the reference beams, and then read out to create a time-reversed image; only the light that was encoded with ultrasound is unaffected by multiple scattering.

Singapore Armed Forces has doubled the number of candidates available for critical jobs such as pilots, commandos and navy drivers over the past five years by paying for the S$2,000 photorefractive keratectomy surgery for shortsighted personnel, the newspaper reported today.