http://www.vision-research.eu/ The European Vision Institute, website hosted by U-Tübingen
http://www.scholarpedia.org The peer-reviewed open-access encyclopedia
https://sph.uth.edu/retnet/sum-dis.htm RetNet: Genes/Loci causing retinal disease
https://web.stanford.edu/group/vista/cgi-bin/wandell/a-brief-organized-list/ Useful numbers in vision
http://www.cvrl.org/ Andrew Stockman's cone fundamentals
http://www.color-blindness.com/farnsworth-munsell-100-hue-color-vision-test/ Colorblind?
https://galactic.ink/sphere/ Find your favorite colors for figures and design
http://www.palamedestoolbox.org/ Matlab routines for analyzing psychophysical data
https://github.com/wichmann-lab/psignifit Psignifit 3.0 for Matlab
http://www.calctool.org/CALC/phys/optics/f_NA Calculate that Airy disk diameter
http://pages.jh.edu/~signals/convolve/index.html Explore the joy of convolution
http://www.hans.strasburger.de/psy_soft.html The definitive link, software and ref resource
http://www.michaelbach.de/ot/ An excellent resource on visual illusions
https://michaelbach.de/fract/index.html THE tool to assess human acuity and hyperacuity