No abstract

Some reports claim that positive suggestion (e.g., using hypnosis) can significantly improve visual acuity (e.g., in myopes). Based on behavioral, neurocognitive, and ophthalmological findings, the authors provide a critical account to review and challenge some of these data. While acknowledging the relative merits of hypnosis for investigating visual phenomena, an array of arguments converges to propose caveats to the apparent influence suggestion can exert on visual acuity. The authors argue that neither suggestion nor hypnotic phenomena are likely to significantly improve myopic vision and contend that a responsible scientific attitude should carefully outline what hypnosis and suggestion cannot do in addition to what they can. It seems likely that the small apparent influence of suggestion on visual acuity is mediated by changes in attention. The authors outline how attention can affect visual acuity.

Psychological approaches to improving vision present an enticing alternative to invasive procedures and corrective lenses; hypnotic suggestion is one such technique. During the past 60 years, multiple studies have documented improvements in the vision of myopic individuals after hypnotic interventions. Given the increasing interest in behavioral and alternative approaches, we have reviewed the pertinent studies to evaluate their validity. We delineate various shortcomings in these reports, including potential methodological caveats, problems with experimental controls, and controversial data interpretation. Overall, the data do not seem to support hypnosis as a viable option for significant long-term improvement of myopia. However, hypnosis can increase one's subjective feeling of enhanced visual acuity by affecting higher cognitive functions, such as attention, memorization, and perceptual learning, which could influence performance on visual tasks.