A myth of the LASIK industry is 'the brain adapts'. What they actually mean is that patients with minor visual disturbances forget how sharp and clear their vision was prior to LASIK. This is why LASIK surgeons like to do both eyes of a patient at the same time. The LASIK industry counts on this 'neural adaptation', encouraging patients to 'give it time'. 'Neural adaptation' does not mean patients see as well as they did before LASIK with glasses, and it does not make them any safer on the roads at night.
Patients with severe visual aberrations (typically patients with large pupils) cannot 'adapt'. It's absurd to suggest that patients can 'adapt' to not being able to see. There's nothing wrong with their brains... the problem is with their eyes! If the image that a patient sees is out of focus, it's out of focus, period.
Marguerite McDonald, MD, said that while patients can be ablated perfectly, some will simply never be happy. "Some patients have 20/20 vision but 20/400 minds," Dr. McDonald said. She suggested that surgeons need to evaluate their patients closely to see who will make good candidates, not just physically but psychologically as well. Source: Michael J. Walsh, OCULAR SURGERY NEWS U.S. EDITION. Some foresee limitations in wavefront technology. August 1, 2002.
James J. Salz, MD: "...I have heard bilateral LASIK advocates seriously state that this is one reason to do the two eyes together, so that the patient can’t compare the LASIK eye with the contact lens eye!"
"Patients also can adapt to visual symptoms in the postoperative period, resulting in a perceived reduction of problem reports. Because there was a delay between treatment of the first and second eye at the 1-month examination, patients had an untreated eye to compare with the visual results of the treated eye. This may have limited their ability to adapt and may have contributed to their report of such problems..."
Source: Ophthalmology. 2003 Aug;110 ( 8 ) : 1606-14. Pupil size and quality of vision after LASIK. Schallhorn et al
"Reduction in night vision complaints over time is in part due to the central nervous system adaptation and this neural plasticity varies among individuals."
Source: Topography-guided CATz Versus Conventional LASIK for Myopia With the NIDEK EC-5000: A Bilateral Eye Study
J Refract Surg Vol. 22 No. 8 October 2006. Mansoor A. Farooqui, FRCSEd; Abdul Rahman Al-Muammar, MD, FRCSC
Jack T. Holladay, MD: "Our refractive surgical goal should be to eliminate or at least reduce all of the optical aberrations of the eye, including spherical aberration. We should remember, however, that it may take 6 to 12 months of neural adaptation for the patient to fully appreciate and exhibit improvement in subjective measures such as visual acuity and contrast sensitivity function."
Source: Cataract & Refractive Surgery Today, Nov 2006
Pablo Artal, PhD: "Many patients' complaints about unwanted visual phenomena disappear without any apparent reason except the passage of time... It is important to note the role of time in neural adaptation. Moreover, although it is obvious that the visual system cannot deal with a very large amount of aberrations, it is also relevant to understand the amount of aberrations that is required to induce the adaptation."
Source: Cataract & Refractive Surgery Today, Aug 2007
"Finally, neural adaptation plays a role in how the brain deals with HOA. It may take 1.5 years to realise better visual performance, which may well be age dependent, with older patients needing more time."
Source: EUROTIMES, Oct 2007
Steven E. Wilson, MD: "You can’t have 20/15 vision with a 20/40 brain."
Source: Eurotimes, April 2004. Wavefront custom ablation, what are we missing?
Depending on the lens and the patient, neuroadaptation may happen sooner, later or not at all. The majority of patients will adapt to multifocal IOLs within six to 12 months, according to Dr. Maloney. But about 10 percent of patients never will adapt. "There are times when a patient who is having serious vision problems during the six to 12-month postop period will say, ‘I’m not willing to endure this any longer, I want these lenses removed.’ "
Source: EyeNet Magazine, July 2007
"The plus side for multifocal IOLs, Dr. Holladay said, is the neural adaptation that takes place over time in patients implanted with the lenses. By 1 year postoperative, he said, the patient’s brain adapts to the new way visual information is being delivered to it, and patients who were at first unhappy become more contented." ... "It is vital to perform bilateral implantation of multifocal lenses in order to allow the neural adaptation to take place, Dr. Holladay said." ... “Always implant multifocals in both eyes,” he said. “By 6 to 9 months, the neural adaptation will kick in, and the amount of unhappy patients will dwindle down to less than 1% or 2%.” "
Source: OCULAR SURGERY NEWS 9/15/2005 Presbyopia correction presents optical challenges