Hi there
For the right kind of cases, Ortho-K is just as effective at correcting vision/spectacle power as spectacles or regular daily wear contact lenses.
Ortho-K (or orthokeratology in full) refers to the use of a rigid (hard) contact lens that is worn at night while sleeping to flatten certain parts of the cornea (the clear window at the front of the eye). This flattening occurs as the lens presses lightly on the cornea the whole night, so that the cornea is molded into a shape that is more similar to the shape of the lens. As can be expected, once the lens is removed during the day, the cornea slowly returns to its original shape. And the original spectacle power also correspondingly returns. Therefore the Ortho-K lens needs to be worn every night to sleep to maintain its effect during the day.
For low spectacle powers eg below about 500-600 degrees of shortsightedness, the results can be quite good with good vision maintained during the day while awake. With higher spectacle powers, some problems may occur such as significant short-sightedness and blurring returning during the day time, and sometimes glare and halos around lights at night.
As with any option for correcting vision, there are pros and cons. The pro of Ortho-K is generally good day time vision without glasses - so it is good for eg water sports where glasses would get in the way and regular contact lenses may confer an increased risk of infection if worn. On the flip side the cons of Ortho-K include the higher risk of corneal infection (due to wearing the lens while asleep), and the problem of fluctuating spectacle power if for whatever reason the lens cannot be worn (eg eye redness or irritation).
Of course, glasses also have pros and cons-the latter of which include a restricted field of clear vision, misting up, and getting in the way of certain activities.
At the end of the day, you should discuss the various options with your eye care practitioner, consider each option's pros and cons and how it applies to you and your lifestyle, and then go with the one that suits you best.
