By contrast, the aberrated eye reflects a distorted wavefront. The local slope of the wavefront is now different for each lenslet and therefore the wavefront will be focused into a disordered collection of spot images.

By analyzing the displacement of each spot from its corresponding lenslet axis, we can deduce the slope of the aberrated wavefront when it entered the corresponding lenslet. Mathematical integration of this slope information yields the shape of the aberrated wavefront.