Hard contact lenses used in orthokeratology, a non-invasive technique to reduce nearsightedness and astigmatism, have long proved to be effective. A new study explains why they are successful.

Patients receiving orthokeratology treatment wear hard contact lenses overnight and wake to clearer vision. The study by Korean researchers, published in the March issue of Optometry and Vision Science, shows that the lens works because it flattens the front surface of the cornea. Scientists had been wondering whether the lens reshapes just the front surface of the cornea or the entire cornea.

The Korean researchers conducted their research on 18 young adults with relatively mild myopia who wore the lenses for 14 consecutive nights. After the first night, the front surface of the cornea had been significantly reshaped, and vision showed a marked improvement. After 14 nights, the participants had near-normal uncorrected vision. Approximately 80% of the improvement occurred over the first 4 nights.

Source:

http://www.sciencedaily.com/releases/2013/03/130304123124.htm