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Myopia Persists After LASIK
I'll begin with a gentle warning. You may need to read this post TWICE in order to grasp its full meaning. Here goes!
Most folks receiving LASIK refractive surgery are nearsighted myopes. The nearsightedness is usually due to longer-than-normal axial length of the eyeball. Axial length is the total distance from the front of the eye to the back of the eye. Myopes wear spectacle corrections with minus lens corrections: -3 diopters, -6 diopters, -12 diopters, etc. As most folks know, LASIK changes the optics of the clear cornea so that after LASIK many nearsighted patients end up with zero diopters of refractive error. Are you with me so far?
Now the hook, even though post-LASIK nearsightedness is eliminated the eyeball itself remains myopic. The axial length of the eye remains long. Only the cornea had surgery - everything else is unchanged. Why should this matter?
Let's use wallpaper to explain the point. Three homeowners are each given six rolls of expensive wallpaper to decorate their dining room. One home has a small dining room, one has an average-sized dining room, and the last has a huge banquet hall. Each has to make do with the wallpaper they were given.
Regardless of eyeball size we are all born with the same amount of retina. Longer, myopic eyes have a much larger internal surface area, and so the myope's retina is often stretched thin to completely line the inner eye. Thin, overstretched retinas are more prone to retinal detachment (RD) and other related problems.
A recent study in the Journal of Refractive Surgery statistically analyzed 59,000 LASIK cases. Fortunately, the LASIK procedure itself does not appear to increase the risk for developing RD - that's good news. The authors did emphasize, however, that moderate and high myopes (-8 diopters and more) corrected with LASIK experience RDs with the same frequency as comparable myopes who never had LASIK performed. Once a myope always a myope.
Bottom line: Even if refractive surgery eliminates your need for glasses it never eliminates the need for regular periodic evaluations by an experienced eyecare professional.
REFERENCE: Faghihi H, Jalali KH, Amini A, et al. Rhegmatogenous retinal detachment after LASIK for myopia. J Refract Surg 2006; 22:448-52.
Related Topics:
Technorati Tags: LASIK, nearsighted, eye surgery, laser surgery, myopia
Most folks receiving LASIK refractive surgery are nearsighted myopes. The nearsightedness is usually due to longer-than-normal axial length of the eyeball. Axial length is the total distance from the front of the eye to the back of the eye. Myopes wear spectacle corrections with minus lens corrections: -3 diopters, -6 diopters, -12 diopters, etc. As most folks know, LASIK changes the optics of the clear cornea so that after LASIK many nearsighted patients end up with zero diopters of refractive error. Are you with me so far?
Now the hook, even though post-LASIK nearsightedness is eliminated the eyeball itself remains myopic. The axial length of the eye remains long. Only the cornea had surgery - everything else is unchanged. Why should this matter?
Let's use wallpaper to explain the point. Three homeowners are each given six rolls of expensive wallpaper to decorate their dining room. One home has a small dining room, one has an average-sized dining room, and the last has a huge banquet hall. Each has to make do with the wallpaper they were given.
Regardless of eyeball size we are all born with the same amount of retina. Longer, myopic eyes have a much larger internal surface area, and so the myope's retina is often stretched thin to completely line the inner eye. Thin, overstretched retinas are more prone to retinal detachment (RD) and other related problems.
A recent study in the Journal of Refractive Surgery statistically analyzed 59,000 LASIK cases. Fortunately, the LASIK procedure itself does not appear to increase the risk for developing RD - that's good news. The authors did emphasize, however, that moderate and high myopes (-8 diopters and more) corrected with LASIK experience RDs with the same frequency as comparable myopes who never had LASIK performed. Once a myope always a myope.
Bottom line: Even if refractive surgery eliminates your need for glasses it never eliminates the need for regular periodic evaluations by an experienced eyecare professional.
REFERENCE: Faghihi H, Jalali KH, Amini A, et al. Rhegmatogenous retinal detachment after LASIK for myopia. J Refract Surg 2006; 22:448-52.
Related Topics:
Technorati Tags: LASIK, nearsighted, eye surgery, laser surgery, myopia
