Wavefront measurement methods discussed

The only constant in the relatively young life of refractive surgery has been change. Even now as our patients reap the rewards of decades of research in the form of customized wavefront ablation, currently unforeseen improvements are inevitable.

Editor’s Note: In the following article, Barrie Soloway, MD, describes why he believes the Zernike polynomial is the optimal methodology for describing wavefront error. In another report , the role of the Fou- rier-based fitting method as an alternative to Zernike polynomials is covered.

For instance, the Zernike polynomial's role as the optimal methodology for describing wavefront error has recently been challenged.

As this alternative makes inroads into the Zeitgeist of refractive surgery, a pair of questions must be answered. Why has Zernike reigned as the optimal choice for wavefront error measurement, and is the proposed use of Fourier an example of implementing change simply for the sake of change?

To illustrate this, the effects of higher-order aberrations on two sets of eyes were compared (Figure 1). The data in blue represent 100 normal eyes prior to any refractive treatment, and show that beyond the sixth order there is essentially no impact. The data in red represent 20 eyes with high levels of higher-order wavefront error.