You might have come across eye centers touting outrageous offers of "20/20 vision or your money back". The whole concept of 20/20 vision has been ballyhooed immensely when it comes to laser eye surgery. In essence, the value 20/20 refers to a way of measuring visual acuity via the Snellen eye chart – the same old alphabet chart that you might have seen at a nearby eye care center. As an instance of Snellen measurement, people with 20/40 vision can see clearly at 20 feet what people with 20/20 vision can see clearly at 40 feet.
With the latest technological advancements in laser eye surgery, the conventional LASIK procedure has been augmented with superlative techniques like wavefront LASIK, and its add-on, iris registration. With such enhancements there is an even greater chance of 20/20 vision relative to that with conventional LASIK. By wielding wavefront technology there is a great, around 95%, chance of 20/20 vision. However, with the iris registration technology, the possibility of 20/20 vision skyrockets to an overwhelming 99%.
20/20 vision is what you aim for while undergoing any type of refractive surgery – it's used as a benchmark. However, some people hold a somewhat dissenting opinion about 20/20 vision, as far as laser eye surgery is concerned. The argument put forth is that visual quality matters more than visual acuity. As is evident from a number of cases, laser eye surgeries, for instance LASIK, have potential complications. A patient might experience blurry vision, halos, ghost vision or double vision, glare, and starbursts surrounding light sources at night.
Normal vision is crisp and sharp. But after laser eye surgery, a person might have to deal with debilitating side effects, which typically diminish vision quality. Though the patient might still be able to decipher a 20/20 line on the Snellen chart, the vision might be blurry. Unless the complications subside, eye surgeons' famous promise of 20/20 vision is merely a myth.
In general, the degree of refractive error and the pupil size are the only criteria while determining the candidature of a patient for laser eye surgery. Most patients are not tested on other grounds, such as contrast sensitivity, glare and depth perception. The data pertinent to such aspects is fairly anecdotal. A comprehensive preoperative test regime is necessary for achieving authentic 20/20 vision (with enhanced vision quality) after laser eye surgery.
If you find a LASIK surgery that you are confident with, you will be able to get more information about 20/20 vision.