What should I look out for when selecting a SH wavefront aberrometer?
Not all Shack-Hartmann wavefront aberrometers are alike. Different manufacturers offer products with varying degrees of accuracy, dynamic range, max./min. pupil diameters, analysis features and compatibility with other devices. Two of the key factors when choosing a Shack-Hartmann aberrometer are accuracy and dynamic range. Accuracy, is directly linked to the number of points measured and the spread of these measuring points. The higher the number of points the better, but some aberrometers underachieve because of an uneven spread of the points, even though they have a high number of them. Sometimes manufacturers use software algorithms to enhance the optical resolution of their wavefront sensors; this is called software interpolation. This process takes data from nearby points to calculate, by approximation, what the desired added data points would be if they could be measured physically. The inherent room for error with this type of technology is evident because the device is not pro
