PrismGlass.com

Eluzions' Optical Illusions
Contains many optical illusions, illustrating a wide range of visual anomalies and surprising optical effects. A free screensaver, posters, and educational explanations are also provided.
eluzions.com/

Optical Magic Optical Illusions
A selection of common images.
www.goodtricks.net/

Optical Illusions Etc
Contains many optical illusions in blog format.
illusionsetc.blogspot.com/

Optical Illusion Archive
A collection of optical illusion images, 3D street art, and flash demonstrations.
www.unoriginal.co.uk/

Drews Optical, Inc.
Manufacturer of custom precision flat optics. Specializing in odd shapes and sizes up to 24 inches in diameter. California.
www.drewsoptical.com/

Electro-Optical Products Corporation
Manufactures optical modulators, choppers, shutters, scanners, galvos, and drivers. New York
www.eopc.com/

Laser & Optical Technologies
Manufacturer of optics including lenses, mirrors, windows, and assemblies. Bulgaria.
www.laserandopticaltechnologies.com/

Mchael Bach: Optical Illusions & Visual Phenomena
The stress here is on relative novelty and interactivity, in combination with a scientific background. Regularly updated.
www.michaelbach.de/

Cool Optical Illusions
A growing collection of optical illusions and eye tricks, including original illusion pictures and a collection of optical illusion desktop wallpaper.
www.coolopticalillusions.com/

Optical Illusions?
Comments on the terms 'Optical Illusion' and 'Visual Illusion'.
www.anc.ed.ac.uk/