December 2010




Personality, perception & outcomes

by Matt Young EyeWorld Contributing Editor

Individuals who believe their parents are disappointed in them tolerate blur better than those who think their parents are satisfied with their achievements. Although this may sound like an unusual scenario of cause and effect, a new study, published online in May in Investigative Ophthalmology & Visual Science, has verified this and other unusual links between psychological factors and tolerance of blur. It all adds up to this conclusion: individual personality influences tolerance of blur. "The results support our preliminary specific hypothesis that overall psychological adjustment and tolerance of blur are negatively correlated and imply that some form of maladjustment might be related to blur tolerance," reported lead study author Russell Woods, Ph.D., Schepens Eye Research Institute, Boston. While fascinating, the study may also have significant clinical implications. Dr. Woods and colleagues are working on developing a questionnaire administered in a clinical setting related to blur tolerance and personality that could help improve success rates with visual correction.

Who tolerates blur?

Dr. Woods analyzed 99 subjects with normal vision. Blur tolerance measurements were performed on one eye in each person. "A computer-controlled Badal optometer was used to measure noticeable and objectionable perceived blur," Dr. Woods reported. "Responses to positive lens defocus were measured while viewing three letters presented on a computer monitor.

Noticeable Blur was described as 'the point where you first notice a change in the crispness and sharpness of the letters.' Objectionable Blur was described as 'the point where blur reaches a level that you would refuse to tolerate on a full time basis. The blur has just reached the point at which it is not acceptable. You would not tolerate spectacles or contact lenses that made you see this way.'"

In addition to other measures taken to pinpoint a subject's individual blur tolerance, participants' personalities were also assessed. Subjects completed the NEO Five-Factor Inventory and California Adult Q-Sort personality measures. Results from blur tolerance analysis indicated that subjects had a wide range of such tolerance, from 0 D to 3.1 D. "We hypothesized that psychologically well-adjusted individuals would not tolerate blur as well as individuals who were poorly adjusted," Dr. Woods reported. "Positive correlations found with the Parental Criticism and Doubts about Action subscales suggest that individuals who believe their parents are disappointed in them are more likely to tolerate blurred vision than individuals who believe their parents approve of their achievements and that individuals who perceive themselves to be ineffective are more likely to tolerate blur than self perceived effective individuals."

Hence, psychological adjustment and blur tolerance appear to be negatively related, although Dr. Woods called for further research. Further, principal factor analysis unveiled two psychologically meaningful categories, also called factors. These were "low self-confidence" and "disorganization." "These factors suggest that people who lack self-confidence may require strong evidence of blur before they become annoyed by the blur of an image or from a device, and that disorganized people may tolerate blur because it is simply another manifestation of their untidy personal environments," Dr. Woods reported. Dr. Woods suspects personality affects responses to images well beyond blur tolerance. "Tolerance of blur may be related to perception of image quality," Dr. Woods reported. "If so, personality may influence responses to an imperfect image in many situations such as refractive error development, refractive error corrections (e.g. progressive addition lenses, multifocal contact lenses and intraocular lenses, or refractive surgery), central vision impairments (e.g. macular degeneration), and viewing compressed images or videos (e.g. bandwidth-limited content)."

Dr. Woods is working on investigating personality factors in another group to confirm the relationship between personality and blur as well as to develop a simple questionnaire that could be used clinically "to indicate how likely an individual would be to tolerate interventions that may induce blur."

Mark Packer, M.D., clinical associate professor of ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Ore., views this line of research as a bit odd. Even if true, how would one go about asking patients about their relationship with their parents in a way that doesn't sound offensive, Dr. Packer wondered. "I don't know if I would want to get into that with patients," he said. Still, Dr. Packer said he might consider consulting with a patient's therapist to "get some advice in a general way" on a particular procedure. Altogether, Dr. Packer believes there are so many sides to the question of who's a good candidate for refractive surgery that he doesn't believe questionnaires would determine that. "I let the conversation with the candidate happen and do what I think is right," Dr. Packer said.

Editors' note: Dr. Woods has no financial interests related to this study. Dr. Packer has no financial interests related to his comments.

Contact information

Packer: 541-687-2110,
Woods: 617-912-2589,

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