Slide 10 of 19

Notes:

• I return now to the question of gold standards. Here is a picture of the model eye Applegate built for calibrating systems for measuring aberrations of the eye. It has lots of useful features, as listed on this slide.

  We decided to use this model eye for our empirical comparison of the Howland and S-H aberrometers, but then we ran into all of the thorny questions mentioned earlier.

  To make matters worse, we mistakenly thought it would be a simple matter to have our colleague Jim Schwiegerling calibrate the lenses used in the model, and to ask David Atchison, who designed and built the lenses used in the model, to calculate its aberrations theoretically from the lens parameters. Needless to say, when we tried to compare the 4 different methods for calibrating this model eye we got 4 different answers using 4 different schemes for specifying aberrations! That is when we realized that we, meaning the visual optics community, has a real problem on its hands. To quote Paul Newman's fictional character, Cool Hand Luke, "what we had here was a failure to communicate."

  It seemed to us that our one experience, or something similar, has probably happened to everyone who has attempted to measure the aberrations of the eye. So, it seemed that it was about time we did something about it, which is when the idea of a taskforce came to mind as a mechanism for setting some standards in our field and bring some order to the chaos.