Refractive lens exchange is set to become a very prominent procedure in the very near future. The next generation of accommodating IOLs is going to afford an absolutely great cure for presbyopia—a condition which affects absolutely everyone on the planet. And this will be a huge break for ophthalmologists and a huge benefit to patients.
Because it’s an elective procedure on an eye that is correctable to sharp vision with glasses, you have to have confidence in your ability to perform surgery on the normal eye for refractive lens exchange. Other than having a refractive error and the associated presbyopia, these are normal eyes so you have essentially zero margin for error.
There are two keys to RLE success: You have to educate patients to set their expectations appropriately, then, deliver the perfect outcome. The bottom line is that we’re very accurate compared to where we were 5 to 15 years ago with regard to delivering accurate vision. This is due in large part to the new optical ways of measuring axial length, newer IOL power calculation methods, and newer ways of correcting astigmatism.
We’re going to start seeing a shift towards what many are calling “Bioptics”. Bioptics is where make your typical Lasik flap, do your intra-ocular procedure (putting the lens in), then if you need to, go back one month post-op, lift the flap and do a bit of Lasik touch-up to correct for residual astigmatism, myopia, or hyperopia and get the exact post-op refraction you want. With femtosecond lasers like the Intralase this becomes a very easy procedure. If needed you can do astigmatism management by limbal relaxing incisions LRIs post-op, or by shifting the main incisions for the surgery in pre-op planning.
From the surgical perspective, you absolutely can’t make any mistakes intra-operatively. There is no tolerance for an irregular or radialized capsulorrhexis, because you then can’t put in the currently FDA-approved accommodating IOLs. During the surgery, with this essentially normal lens which is much softer than a cataract, it’s less about phaco power and more about fluidic imbalance. A clear lens doesn’t require any phaco energy. It can be done quite gently using the fluidics of the phaco machine. Two notable new phaco machines on the market are designed purely around having superb fluidics: the Bausch & Lomb Stellaris™ Microsurgical System, and the AMO WhiteStar Signature™ phacoemulsification system. Your existing phaco machine may work, but you really need to ensure that your fluidic balance has been optimized. This means keeping the inflow of fluid higher than your outflow of fluid and using other methods to maintain stability during surgery.
If your fluidics are mismatched and your outflow of fluid exceeds inflow for just a fraction of a second you’ll see surge and you can even collapse the stability of the anterior chamber and break the posterior capsule. At that point you’re in trouble and you can’t put in your premium accommodating lens.
It really all boils down to fluid kinetics -- prevent surge and keep a high margin of safety. Adding to the problem is that as many surgeons are moving towards tiny incisions (2.2mm , 2.0, sub 2.0, 1.8,…) the amount of fluid available for inflow is less, and this can make things less stable. Clearly, a higher margin of safety is required.
Refractive accuracy is required in order to meet or exceed patient expectations. You have to be super exact in your lens calculations and you have to track your results. Follow your patients and see what you ended up with vs. what you had predicted, then go back and hone your calculations and refine your A-constants.
The era of Refractive Lens Exchange being a dominant procedure is coming. The baby boomers will want to achieve a high degree of spectacle freedom in order to enjoy their active lifestyles. With a high degree of safety and a high degree of surgical accuracy, we can meet their needs and exceed their expectations.
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