Modern popular refractive surgery started with a microsurgical procedure called radial keratotomy (RK). Here, four to eight cuts are made in a spoke-like pattern in the peripheral cornea causing it to weaken and bulge out slightly. This in turn causes the central optical zone to flatten, simulating the effect of placing a concave lens on the eye.

RK actually had it roots over 40 years ago in Japan. However, it was only in the 70's, when the technique was improved upon by the Russian eye surgeon Fyodorov, that refractive surgery started to gain popular acceptance. But it never really took off in a big way as the results were often unstable and unpredictable. The healing process was also slow and painful.





Laser refractive surgery was developed as a way to improve the accuracy and predictability of microsurgery. The advent of the excimer laser finally made this a reality. The laser was first developed and used way back in the seventies by the computer industry for the precise etching of computer chips. It was just the kind of delicate tool eye surgeons needed to sculpt the refractive power of the eye directly onto the cornea with precision and minimal damage.

The procedure was called photorefractive keratectomy (PRK) and the first cornea application of the excimer laser to the human eye happened in 1983. But it was only in the early nineties with treatment protocols and guidelines established that PRK moved beyond the experimental stage. Results for mild to moderate myopia were encouraging with 95% of patients seeing 6/12 or better post-op. 6/12 is the minimum vision requirement for driving in most countries. PRK slowly but surely began to overtake RK in popularity.



However, PRK never really took off in a big way as it took three days for the treated surface of the cornea to heal during which the eye is teary and painful. Vision was also unstable for the first few months with an initial phase of over-correction before the power finally settles down. Treatment of high myopia was also less than satisfactory with major problems of unpredictability and severe cornea hazing in some patients.



Then it was found that by using the laser to treat the deeper layers of the cornea, all these drawbacks could be surmounted. To achieve this, the excimer laser technique was combined with an established cutting technique called keratomileusis to create a superficial cornea flap. Hence we have the modern technique of Laser-In-Situ-Keratomileusis or LASIK. The first Lasik procedure was done in 1989.