Suppose there is air at one side of a lens, and water at the other, such as in the human eye. Is the focal length for light in the direction from air to water then different from that for light in the opposite direction?

If the focal distances are different, the three special light rays that are commonly used for constructing the image of an object no longer intersect in a single point. Is this problem solved by allowing only two special rays for a given direction?

  • $\begingroup$ Is this question because you can shoot lasers from your eyes? :) $\endgroup$ – Aaron Stevens Nov 17 '18 at 12:46
  • $\begingroup$ Maybe the eye is not a great example, but the question remains the same. $\endgroup$ – jkien Nov 17 '18 at 13:04
  • $\begingroup$ They should be different, but I'm not in a place to type out a full answer explaining why $\endgroup$ – Aaron Stevens Nov 17 '18 at 13:25

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