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C. Kent

New eyeglass lens technology sharpens eyesight after LASIK

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Most people who have LASIK are very pleased with their new vision without glasses. But in some cases, a person may feel their eyesight isn’t as distinct after surgery as it was with eyeglasses or contact lenses. Even if they can see letters on the “20/20” line on the eye chart, their vision might not be as “sharp” as they remember.


In many cases, a second LASIK procedure (called an enhancement) can be performed to improve visual clarity and satisfaction. But enhancement surgeries tend to have a higher risk of complications than first-time LASIK procedures, and sometimes an enhancement is not recommended, such as when the patient’s cornea is too thin for additional surgery.





When a person is dissatisfied with their vision after LASIK, it is usually due in part to subtle optical imperfections called higher-order aberrations, or HOAs. These imperfections can cause or contribute to blur, glare, loss of contrast, and night vision problems (including starbursts and halos around street lights and vehicle headlights).


Research suggests that prior to vision correction surgery, up to 20 percent of a person’s vision problem can be due to HOAs. After LASIK surgery, this percentage can be much higher. And nearly all of us — whether we’ve had vision correction surgery or not — have some degree of higher-order aberrations. At least one study suggests that 96 percent of nearsighted individuals have significant levels of HOAs.


Unfortunately, unlike refractive errors (nearsightedness and farsightedness, with or without astigmatism) higher-order aberrations cannot be addressed with conventional eyeglasses. People who feel the need for corrective lenses for night driving after LASIK often find regular eyeglasses provide little or no help in sharpening their eyesight.





Until recently, the prescription for eyeglasses, contact lenses and refractive surgery such as LASIK, was determined by a traditional refraction. This process, performed by a machine (automated refractor) or done manually by your eye doctor (by dialing different lenses in front of your eyes and asking, “Which lens is better — lens 1 or lens 2?”) is not able to identify the HOAs that affect vision.


To address this shortcoming of traditional vision correction, optical technology called wavefront analysis was adapted for measuring eyes prior to LASIK surgery. In wavefront analysis, a special automated instrument called an aberrometer is used to detect and measure higher order aberrations as well as traditional refractive errors. Wavefront analysis provides a very precise mapping of the surface of your eye that details both the traditional refractive error and HOAs. These highly-detailed measurements are then used to program the excimer laser in wavefront-guided LASIK to provide better outcomes than standard LASIK.


But as precise as wavefront-guide LASIK is, every person’s cornea responds to laser energy uniquely and heals differently. And the laser treatment itself induces some HOAs while it corrects others. So in many cases, significant HOAs remain after LASIK surgery — even after the more precise, wavefront-guided procedure.





Ophthonix, Inc. (Vista, CA) saw an opportunity to use the advances of wavefront technology to create a new generation of eyeglass lenses capable of addressing HOAs as well as refractive errors. The wavefront-guided lenses created with this technology — called iZon® High Resolution Lenses — are capable of producing sharper vision than conventional eyeglass lenses. According to the company, iZon Lens provides wearers with the benefit of “High-Definition Vision.”


Though iZon Lenses are available for anyone who needs corrective lenses, they are especially good “problem-solver” lenses for individuals who’ve had LASIK or other vision correction surgery and still have issues with their eyesight.



* * * READ THE REST OF THIS STORY AT www.LasikSurgeryNews.com * * *

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