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    Vision Experts Don't See Eye to Eye in Quest for Perfect Sight


    In addition, our ability to map visual errors currently outpaces the ability to do anything about them, says Ernest W. Kornmehl, MD, director of a refractive surgery center in Brookline, Mass., and clinical instructor in ophthalmology at Harvard Medical School.

    "Theoretically, yes, we can get down to between 20/5 and 20/10 vision. However, our ability to measure these [minor errors] that reduce vision is better than the current technology to correct them," he tells WebMD. "It all sounds great, but when you look at the brass tacks it's a little bit more involved. For instance, these aberrations change as we age: the lens changes and the other parts of the eye change, and the question is -- no one knows the answer to this -- will this induce new aberrations? And [if it does,] we'll drop to 20/15 or 20/20, which wouldn't be a bad thing, but we still have to obtain that information."

    Thibos says that there are factors in the eye that can vary over the short or long term, such as changes in the ability of the lens to compensate for changes in near and far vision (an ability that declines with age), tear-flow irregularities, and abnormalities in how we see colors. All of these things may ultimately affect the quality of the retinal image.

    In addition, even if "perfect" retinal images are achievable, the end user -- the patient -- may be unhappy with the results. Thibos points out that computer monitors, television screens, and the printed page all take advantage of the fact that our eyes can't perfectly discriminate fine details such as pixels, scan lines, or dots of ink, and instead blend the images into seemingly sharp pictures.

    Ultimately, though, Kornmehl says, patients and eye surgeons might be better served by remembering that "perfect" is often the enemy of "good."

    "There's no guarantee of perfection," he tells WebMD. "Many people say we've improved their lives, they're happy and they're thrilled and it enriches their lives tremendously, but if people are looking for perfection -- far, near, close, forever -- no, of course not. It's wonderful what we're doing, but people have to maintain a certain perspective as well."

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