It is difficult to imagine a more comprehensive collection of interlinked items for covering Optics and Vision. The tree structure in which the topics are arranged, the details with which the branch topics have been dealt with, and the high degree of detail that is available by clicking on virtually every technical term, makes this site a unique resource.
There is extensive coverage of topics at both introductory and more advanced levels. This includes discussions of both thin and thick lenses, lens aberrations, and applications in optical instruments. In addition, there is a fair amount of material on the perception of color and systems for quantifying color measurement. Finally, there is some material on the visual mechanisms in the eye as well as vision defects and methods of correction.