LASIK vs. Lens Replacement Surgery (Refractive Lens Exchange or Clear Lens Extraction): New Study Again Favors Safety Profile of LASIK.

Study shows an ongoing risk of posterior vitreous detachment and retinal breaks after cataract surgery. In the choice of lens replacement surgery vs LASIK, the higher safety profile of LASIK needs to be considered in vision correction surgery choice. In a recent blog, I looked at lens replacement surgery and clear lens extraction as alternatives to LASIK eye surgery for vision correction. Both refractive lens exchange and clear lens extraction involve entering inside the eye, taking out the natural lens (even if there is no cataract in it yet or just a very “early” and visually insignificant cataract), and substituting a new plastic implant which has a prescription in it. The logic behind this approach is that we all get cataracts eventually and this surgery “kills two birds with one stone”: the lens is replaced so that it is now plastic and will never develop a cataract — and the vision is corrected by the prescription built into the lens. New generation premium implants such as the Crystalens, ReStor, and Tecnis Multifocal IOL also allow for some degree of correction of presbyopia (the need for reading glasses) as well.

The downside to refractive lens exchange or clear lens extraction in comparison to LASIK laser vision correction is that these procedures are inherently more invasive and therefore more risky than LASIK. They also are generally less accurate as they do not work in wavefront tolerances as the latest form of wavefront guided LASIK does.

In my previous blog, we looked at the issue of risk and at the fact that there is not only the inherently higher risk at the time of surgery of lens removal compared to LASIK, but there continues to be an ongoing risk to refractive lens exchange and clear lens extraction long after the surgery is done, even if everything goes well. We reviewed the fact that an outstanding new study of lens replacement surgery showed that, while the risk of macular degeneration does not change immediately after lens replacement surgery, it nearly doubles five year after surgery. Macular degeneration is the leading cause of blindness in the United States.

A new study that was just published in the journal of the American Academy of Ophthalmology now looks at a different long term risk of lens replacement surgery: the risk of retinal tears. Retinal tears are potentially very serious as they can lead to retinal detachment, which is a very serious and potentially blinding problem.

In order to understand this important new scientific study, it is helpful to understand the anatomy of the eye. The eye is basically a hollow sphere which is filled with a jelly like substance known as the vitreous. The large back cavity in the eye is lined by the retina much like wall paper lines the walls of a room. The vitreous is attached to the retina. After refractive lens exchange, clear lens extraction, or cataract surgery, the vitreous tends to shift and it can become detached from the retina. This is called a “posterior vitreous detachment” or “PVD”. At the time the vitreous detaches from the retina, it can actually tear a small piece of the retina, much like pulling tape off of wallpaper can cause a tear in the wallpaper. A retinal tear, in turn, can lead to a retinal detachment, which is a very serious problem. Not all posterior vitreous detachments result in retinal tears, however, and not all retinal tears result in retinal detachment.

A recent study from the Ohtsuka Eye Hospital in Sapporo, Japan looked at the rate that posterior vitreous detachment (PVD) happened over a three year period after lens removal and replacement with a foldable intraocular lens (cataract surgery). A total of 575 eyes which did not have posterior vitreous detachment prior to cataract surgery were studied. By 1 week after surgery, 1% of eyes had developed a posterior vitreous detachment. By one year after surgery 11% of eyes had developed a posterior vitreous detachment and by three years after lens replacement surgery, 30% of eyes had developed a PVD. Of these eyes that had developed posterior vitreous detachment after cataract surgery by three years, 6.4% had developed the more serious problem of retinal breaks or tears. In eyes that did not develop posterior vitreous detachment after surgery, there were no cases of retinal breaks or tears.

Also of interest in comparing the option of lens replacement surgery to LASIK is the fact that, in this study, significantly more patients under age 60 had posterior vitreous detachments than those age 71-80, suggesting the risk of posterior vitreous detachment with refractive lens exchange is higher in the age group that might otherwise be considering LASIK as an option. Typically patients age 71- 80 would be less likely to consider LASIK as they would be more likely to have a true cataract already and therefore may have less of an option of using LASIK to correct their vision as LASIK obviously would not address the cataract. Typically it is younger patients with clearer lenses that are weighing the pros and cons of LASIK versus lens replacement surgery.

This study further emphasizes the need to consider all risks when comparing LASIK laser eye surgery to lens replacement surgery (refractive lens exchange) or clear lens extraction — not only the risks at the time of surgery but the ongoing risks after lens replacement surgery is successfully completed. This study shows there may be an ongoing increase risk of serious retinal problems due to fundamentally altering the interior of the eye with lens replacement surgery. The Beaver Dam Eye Study we looked at in my previous blog on this subject showed there also may be an ongoing increased risk of macular degeneration associated with lens replacement surgery.

My reading of the data shows that LASIK, while of course not without its own set of risks, has a higher safety profile than the more invasive lens replacement surgery — both at the time of surgery and on an ongoing basis after surgery.

In my practice I tend to be very conservative. Safety always needs to be the highest priority. after carefully explaining all options, my preference is to recommend LASIK or PRK laser vision correction over lens replacement surgery if the patient otherwise is a candidate and the lens is reasonably clear and it does not appear cataract surgery is otherwise imminent. I prefer to postpone cataract surgery until it truly is necessary. However, if a patient already has a visually significant cataract, or appears to be close to having one, then I recommend cataract surgery with attention to refractive visual goals instead of LASIK or PRK laser vision correction eye surgery.

LASIK vs. Lens Replacement Surgery (Refractive Lens Exchange or Clear Lens Extraction): New Study Again Favors Safety Profile of LASIK.

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