The Pupil

• The "hole" in the iris which allows light into the eye.
• It changes size in response to ambient light level and other things.
• Pupil reflex appears to be triggered by a mixed cone and rod stimulation. Alpern and Campbell '62
• The pupil horizontal diameter ranges from about 2 mm to about 8 mm.
• Some empirical equations describing retina size as a function of light level are:
  • Moon and Spencer (1944): diameter = 4.9 - 3tanh[.4(log L + 1.0)]
  • DeGroot and Gebgard (1952): diameter = 10^(.8558 - .000401(log(L) + 8.6)^3)
  A plot of these functions:

  

  There is a Mailbase list-server devoted to the pupil.

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  visit(s) to this page.

  Lance Hahn(lance@retina.anatomy.upenn.edu)