Femtosecond refractive cataract surgery offers many advantages to patients, physicians

Issue: June 25, 2010

ByRichard L. Lindstrom, MD

Richard L. Lindstrom

Here comes the femtosecond laser again, this time offering improvement in refractive outcomes and safety for the cataract patient and surgeon.

Many of us who are corneal refractive surgeons remember that skeptics were ample when the femtosecond laser was first launched as an alternative to the mechanical bladed microkeratome for construction of the LASIK flap. Ten years later, the femtosecond laser dominates the LASIK field in all of the world’s advanced countries despite its increased cost and the additional time required per procedure. Why, one might ask? The answer is simple. It generates more accurate refractive outcomes, a faster visual recovery and a safer procedure.

Many studies confirm that in most surgeons’ hands, visual outcomes with a single treatment are superior and a lower enhancement rate is generated when a femtosecond laser flap is utilized. More important, sight-threatening complications are reduced significantly. While a few very highly skilled and experienced surgeons can come close to duplicating femtosecond outcomes using a mechanical microkeratome, most surgeons, including myself, found outcomes and safety enhanced with all-laser LASIK.

What about the cost issue? All but a small number of patients, when presented with the opportunity to access a better outcome and increased safety, are happy to bear the extra expense of a femtosecond laser for LASIK.

So, what about femtosecond refractive cataract surgery? Again, it appears the femtosecond laser will be able to enhance our refractive outcomes. The goal remains a defocus and residual astigmatism outcome within 0.5 D of emmetropia. Registries of surgeon outcomes suggest we are achieving this outcome target in only 40% to 50% of cases, even in experienced surgeons’ hands.

The major remaining variable for defocus is our inability to predict the exact position a posterior chamber lens implant will settle after surgery, generally called the effective lens position. Research suggests the best way to increase the reproducibility of effective lens position for any implant is to create a perfectly sized capsulorrhexis. Capsulorrhexis size and centration are also a critical factor in the performance of single- and dual-optic accommodating IOLs. The femtosecond laser has shown itself capable of making a perfect capsulorrhexis every time.

Our other challenge when attempting to reduce spectacle dependence is to reduce astigmatism. Again, a perfect and reproducible incision is the first challenge, and the femtosecond laser seems up to the task. In addition, the accuracy and reproducibility of limbal and corneal relaxing incisions will also be improved with this technology. We will be able to enhance our refractive outcomes regarding both defocus and astigmatism with the femtosecond laser. Thus, femtosecond cataract surgery will be femtosecond refractive cataract surgery, enhancing refractive outcomes and reducing spectacle dependence, therefore making it eligible for patient-shared cost responsibility.

In addition, it is becoming clear that the patient will also benefit from enhanced safety. Perfect wounds are less likely to leak, reducing the chance for hypotony or endophthalmitis. A perfect capsulorrhexis reduces capsular tear rates, vitreous loss and lens decentration. A softer nucleus reduces phaco power and time, sparing the corneal endothelium and reducing further the risk of capsular tear or vitreous loss. Just like femtosecond LASIK, for many patients the enhanced safety will be a deciding factor in their selection of femtosecond refractive cataract surgery for their own or their loved ones’ eyes. The enhanced refractive outcomes will allow us to offer this advanced technology to our patients as a patient-pay option, and the enhanced safety will increase the number who choose this option despite the increased cost.

Finally, intrastromal corneal incisions with the femtosecond laser appear capable of treating astigmatism, myopia, hyperopia and even presbyopia in a range up to at least 2 D to 3 D. This will provide the femtosecond refractive cataract surgeon with a minimally invasive office enhancement without the training associated with LASIK and the delayed visual recovery associated with PRK. A small increase in time invested at the femtosecond laser before bringing the patient to the operating room will increase efficiency in the operating room and reduce time in the eye, where it is the most expensive and the risks are the highest.

I am very excited about this technology for my practice and expect to access it in the next 12 months. Amazingly, the first lasers are already being placed in select practices in the Unites States and abroad. The era of laser cataract surgery is now a reality.