The equivalent of a lens +1.00 +2.50 X 90 is:
a. +1.50D
b. +2.25D
c. +2.50D
d. +3.50D
our answer would be +3.50D however the answer key is saying the answer should +2.25...
Please help me
The equivalent of a lens +1.00 +2.50 X 90 is:
a. +1.50D
b. +2.25D
c. +2.50D
d. +3.50D
our answer would be +3.50D however the answer key is saying the answer should +2.25...
Please help me
Last edited by kristiekyle; 11-11-2014 at 01:51 PM.
Kristie J Meyer
The person who says it cannot be done should not interrupt the person who is doing it. ~~Chinese Proverb
Kristie-
What's the equivalent if the power is +1.00 +1.00 x 45
a +2.00
b +1.00
c +1.50
d none of the above
+1.50 !!! Sorry Uncle Fester the anticipation was killing me
As above answer but background info on what I think your asking.
By the sound of it your wanting to locate to circle of least confusion in a toric prescription.
The location of the circle of least confusion is equal to the spherical equivalent of the prescription:
Spherical Equivalent = Sphere + Cylinder / 2
For example, given a prescription of +1.00 DS +2.50 DC 90, the spherical equivalent (and the location of the circle of least confusion) is given by +1.00 + (+2.50) / 2 = +2.25 D
Does it work very well on PTs with an oblique axis?
Hi Bok,
This notation might be confusing; some might read this as adding the sph to the cyl and dividing that value by 2.
Brackets might work... Spherical Equivalent = Sphere + [Cylinder / 2]
or probably just cozy up the forward slash and the divisor...
Spherical Equivalent = Sphere + Cylinder/2
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.
Last edited by Robert Martellaro; 11-12-2014 at 04:27 PM. Reason: damn spell checker!
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.
Yes I know! This is for math dummies like me who don't absorb formula's the way you do.
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.
Thank you Robert, I have always enjoyed your posts your command of optics is way above mastery of the subject. One of the few on the board that I consider vital to read. Even when I know the answer sometimes your explanation adds knowledge.
Einstein said if you can't explain it simply then you don't understand it as well as you thought (not verbatim).
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