The abbe value of Trivex is the same as the abbe value of the human eye. There is no better material for eliminating Ca why is Prentice rule a rule and not a law.
The abbe value of Trivex is the same as the abbe value of the human eye. There is no better material for eliminating Ca why is Prentice rule a rule and not a law.
Last edited by vfpamp; 02-25-2020 at 08:42 AM.
Human eyes can not detect the chromatic aberration if the Abbe number is above 40. With that in mind, why not 1.6 for +3 and up, or -4 and up? Yes, it is less impact resistant and weighs about CR39, but beyond that, it is thinner, has high tensile strength so it is good for 3 piece and nylor, and the ABBE is 42 vs 44.
I bend light. That is what I do.
Because our eyes suffer from a high degree of axial/longitudinal chromatic aberration, we don't notice it in ophthalmic lenses. Instead, they are affected by transverse/lateral CA.
WRT rule or law, I'd throw in postulates and principles, choose one, and call it a day.
Best regards,
Robert Martellaro
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
True. But what’s often forgotten in the abbe-of-the-human-eyeball discussion is that the blue induced at the retinal plane from color error is always present—even if our eye has evolved to no longer notice it. So the eye’s effective threshold for noticing the blur induced by color error has been artificially (via evolution) elevated.
I believe this is one part of the reason why improper base curve choice, less than optimal lens design choice, and low material abbe can sum up and surpass this not-noticed threshold.
This is especially true for hyperopes wearing progressives and segmented lenses for reading.
B
Yup
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