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17 Cards in this Set
- Front
- Back
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Hard contact lenses: Significant change in BC is (___) and results in what amount of change to power?
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0.1mm = 0.50D change
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The equation to convert power (D) to radius?
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F=0.3375/r
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Javals rule suggests that the average intraocular lens contributes 0.50D (WTR/ATR) astigmatism?
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0.50 ATR
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Draw the fitting flow chart
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2cyl, 3cyl, spec cyl 1.5x K cly,
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Maximum of acceptable residual cyl?
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0.75
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You must vertex the power from over refraction if the power is ___?
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4.00D or more
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If the GP sits too high, what changes can you make?
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Steeper, Smaller, heavier, thicker
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Minimum amout of change for diameter?
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0.4mm
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You must flatten the BC by ___ for every 0.4mm increase in diameter.
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0.25D. Don't forget to change power accordingly.
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A warped lens will show (sphere/cyl) on lensometer. On radioscope?
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Sphere on lensometer, cyl on radioscope
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Two most likely reasons for variable vision with GP's?
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Warpage, flexure
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If flexure is acknowledged, you can assume what type of bending? What does this do to tear film cyc? How do you measure? How do you correct?
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Around steep meridian, decreases amount of tear film cyl. Over-k (keratometry over with lens on eye). Make lens thicker
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A toric soft lens with axis 180 rotates 20 degrees right. Effectively, what axis is the lens now? How do you correct this?
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x020. LARS. change axis of lens to x160
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Regarding soft toric rotation: how much cyl do you get back if the lens rotates 10,15, 20, or 30 degrees respectivly?
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10: 1/3
15: 1/2 20: 2/3 30: 100% |
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If your over-refraction has a sperical equavalent of plano, what does this mean?
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Sphere power is correct
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At what 2 positions does the radioscope show a clear image?
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When the radioscope is focused at the surface of the CL and at the CL's center of curvature.
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What amount of rock does jackson like to have
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1.00 Diopter rock (leave 1.0D difference from an On-K fit)
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