The impact of the ocular Shack Hartmann sensor on improving visual performance

The Shack Hartmann wavefront sensor was adapted to measure the aberrations of the human eye in the 1990s. The ability to rapidly and accurately measure ocular aberrations unleashed a flurry of activity targeting understanding the dynamics of the eye's aberrations, as well as the development of a wide array of technologies to correct these aberrations on an individual basis. This paper describes some of the adaptations necessary to enable the Shack Hartmann sensor to work with the eye, and illustrates several different form factors and novel techniques that have been used to expand the dynamic range of the sensor. Furthermore, some of the revelations of population-based studies of ocular aberrations will be reviewed, including insights into the optical design of the eye. Finally, various means of correcting the measured aberrations including laser refractive surgery, custom contact lenses and even spectacle lenses will be described to illustrate current capabilities of ocular wavefront correction and potential pitfalls associated with the various modalities.