Wavefront technologies: Helping you to decide what's best for your patient

September 1, 2006

Wavefront analysis of the human eye is based on an optical theory that was first developed in astronomy more than 100 years ago, with roots that date back almost 400 years. Astronomers used the technology to reduce higher order aberrations (HOAs) induced by the earth's atmosphere. Recognising the potential of this analysis in ocular refractive surgery, manufacturers have recently introduced wavefront technology into several major laser systems in order to improve treatment outcomes and address HOAs within the visual system.

Wavefront analysis of the human eye is based on an optical theory that was first developed in astronomy more than 100 years ago, with roots that date back almost 400 years. Astronomers used the technology to reduce higher order aberrations (HOAs) induced by the earth's atmosphere. Recognising the potential of this analysis in ocular refractive surgery, manufacturers have recently introduced wavefront technology into several major laser systems in order to improve treatment outcomes and address HOAs within the visual system.

Even if this technique is not used for a direct treatment, it enables surgeons to evaluate the optical effects and postoperative changes following a non-customized treatment or just after a LASIK cut. Based on this additional experience, the ablation profiles can be optimized in a way that they compensate for HOAs, which are expected to be present postoperatively.

To begin to formulate an answer to this, we must first understand the differences between wavefront-guided and optimized approaches.

Simply stated, wavefront-guided treatments use the measurement of all aberrations in an eye, including HOAs, to create an ablation pattern specific to that eye. In doing so, they attempt to correct all pre-existing HOAs without inducing any new aberrations. The data from clinical trials do not show that these treatments reduced pre-existing levels of HOAs in most cases. However, all currently available wavefront-guided treatments induce substantially lower levels of HOAs than their corresponding conventional treatments, which results in better quality of vision for patients.

In contrast, the wavefront-optimized treatment does not attempt to correct or reduce any pre-existing HOAs. Instead, it is designed to prevent the induction of one HOA, specifically spherical aberration. Of all the HOAs, first-generation treatments induced spherical aberration most prominently, resulting in glare, halos, and blurred vision for some patients, especially in dim light conditions. The theory behind the wavefront-optimized treatment is that 80% to 90% of patients do not have a substantial amount of preoperative HOAs and therefore benefit more from a treatment that preserves their existing quality of vision. The theory further holds that wavefront-guided treatments are only necessary for the small percentage of patients with certain preoperative visual symptoms.

The availability of both approaches leaves refractive surgeons wondering which is better for their patients. While no large scale, true head-to-head comparison has been done, the results of individual clinical trials and insights from surgeons who are familiar with both approaches can help to clarify the differences.

Whilst some still question the benefits of wavefront-guided or wavefront-optimized over conventional excimer laser treatment, more and more studies are being published that support the integration of wavefront software into laser platforms. With increasing numbers of ophthalmologists across Europe embracing wavefront technology as the new and improved era of laser refractive correction surgery, which way will you go?

Clearly, this advanced software provides refractive surgeons with a tool that allows them to tailor a treatment specifically to each of their patients, whilst increasing safety and refractive outcomes. Whether or not the data that has been, and will continue to be, presented is enough to convince the majority of European refractive surgeons, remains to be seen.

Here, we provide further information on just some of the approved technologies hitting refractive surgery practices across Europe. So take a look and make up your own mind.