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15 Cards in this Set
- Front
- Back
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focal length
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f = 1/D
f=meters D= diopters |
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Vergence formula
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U + D = V
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Prentice's Rule
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PD = h x D
h=distance in cm D= lens power in diopters |
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Spherical Equivalent
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SE = 1/2cyl + sph
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Retinal image height
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(obj ht/retinal ht) =
(dist from nodal point/17mm) |
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spectacle lens magnification
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M = 2% per diopter of power
assume vertex distance 12mm |
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Transverse Magnification
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M = image distance / obj distance
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indirect ophthalmoscope lens
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M = Deye/Dlens = 60/Dlens
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Axial magnification
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Maxial = M^2
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Simple Magnifier
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M = D/4
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Telescope magnification
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M = Deyepiece / Dobjective
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Refracting power of a spherical surface
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Ds = (n' - n) / r
Ds- refracting power surface (n' - n) difference refracting index r = radius |
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Power of thin lens in fluid
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Dair/Dfluid = (n iol - n air) / (n iol - n fluid)
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reflecting power of spherical mirror
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Dreflecting = 1/f = 2/r
r= radius of curvature |
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IOL power (SRK formula)
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IOL=A - 2.5(AL) - .9(avg K)
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