Blind spot experiment (Purdue University Visual Perception Online Laboratory)
http://www.psych.purdue.edu/~coglab/VisLab/BlindSpot/blindspot.html

Other vision Web links:

Vision Research at Vanderbilt (Vanderbilt Vision Research Center)
http://vision-research.vanderbilt.edu/

Common Vision Problems
http://www.preventblindness.org/sitemap/index.html

Color images of lab manual figures

Figure 1:

Figure 2:

Other images:

Fly eyes:

The number of ommatidia per eye varies from species to species with only a few in ants, to 800 in fruit flies, to as many as 10,000 ommatidia in the compound eye of the horsefly. The compound eye provides information about patterns in the environment and is very good at detecting movement.

The world looks different to an insect because of the compound nature of its eyes and also because it is sensitive to different wavelengths of light than our eyes are.  For example some insects can see into the UV.  Features of plants that are invisible to our eyes are apparent to insects because the patterns of the features are visible in the UV.