Aberrations of the whole eye were objectively measured from early childhood to an advanced age, and the relationship between monochromatic aberrations and age has been shown to fit a quadratic model. The results suggest that the definition of emmetropization should be broadened to include the reduction of higher order aberrations.

A Mueller-matrix polarimeter in transmission mode using two electronically controlled liquid-crystal variable retarders has been developed. Its design, theory and calibration are described. Although liquid crystals have been proposed earlier, this paper is focused on the process of the calculation of the Mueller matrix by a matrix-inversion method, oriented to static systems and in vitro samples. By driving the retarders with appropriate voltages, nine independent pairs of polarization states can be produced (incomplete polarimetry), while the other additional seven pairs are obtained by placing two quarter-wave plates (in the input and output optical paths respectively). This configuration allows extraction of 16 independent measurements of intensity. The Mueller matrix of the sample is calculated from them. The results of Mueller matrices for air, a linear polarizer and a quarter-wave plate are presented. Additional polarization parameters such as retardation, ellipticity or degree of polarization were also computed and some applications of the system are proposed.

Using a unique wavefront aberration-controlled backscattered nonlinear microscope, changes in corneal morphology as a function of depth were characterized for different species (including humans). This allowed a direct comparison among species, which might help to establish the basis of collagen distribution in animal models or to understand diseased corneas.

Nonlinear microscopy (in both tomographic and regular XY imaging configurations) was used to study spatial and temporal changes in the cornea during and after CXL on intact ocular globes. SHG imaging showed changes in the morphology of anterior corneal stroma after CXL. Regular collagen patterns turned into random distributed structures with thicker bundles at some localized areas. This might be a consequence of the corneal thickness decrease as a result of riboflavin-dextran instillation.