Refractive error sensing from wavefront slopes

15 páginas, 8 figuras, 2 tablas.The problem of measuring the objective refractive error with an aberrometer has shown to be more elusive than expected.\udHere, the formalism of differential geometry is applied to develop a theoretical framework of refractive error sensing. At each\udpoint of the pupil, the local refractive error is given by the wavefront curvature, which is a 2 2 symmetric matrix, whose\udelements are directly related to sphere, cylinder, and axis. Aberrometers usually measure the local gradient of the\udwavefront. Then refractive error sensing consists of differentiating the gradient, instead of integrating as in wavefront\udsensing. A statistical approach is proposed to pass from the local to the global (clinically meaningful) refractive error, in\udwhich the best correction is assumed to be the maximum likelihood estimation. In the practical implementation, this\udcorresponds to the mode of the joint histogram of the 3 different elements of the curvature matrix. Results obtained both in\udcomputer simulations and with real data provide a close agreement and consistency with the main optical image quality\udmetrics such as the Strehl ratio.This research has been supported by the Spanish\udCICyT, Grant FIS2008-00697, and Red Española de\udOptometría (Ministerio de Ciencia e Innovación,\udSAF2008-01114-E).Peer reviewe