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23 Cards in this Set
- Front
- Back
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Need to convert plus cyl rx into minus cyl then sphere equiv |
Only be done if the cyl is 0.75 or less |
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Vertex distance |
Applies to more than +/- 4.00 D CAP rule |
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No movement |
Lens is too tight |
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Too much movement |
Lens is too loose |
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There should be |
1 mm of movement after each blink and return to cerner over the cornea |
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Lens diameter should extend beyond |
The limbus by 1-1.15 mm |
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Symptoms of a loose fit |
Air bubble under lens Edges do not hug the eye |
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Tight fit lens |
Air bubbles centrally over the pupil Little or no movement upon each blink |
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K readings : 40 44 46 |
40 - flat 44 - average 46 - steep |
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With vs Against the rule |
+ cyl x 90 or - cyl x 180 ( WTR - cyl x 90 or + cyl x 180 ( ATR |
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44.00 / 45.50 @ 90 |
WTR |
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44 / 45.50 @ 180 |
ATR |
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Lens is too tight / steep |
Increase the BC to 9.0 to fit looser |
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Lens is too flat / loose |
Decrease the BC |
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Lens is too large / big / small |
Diameter problem |
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Spherical lens |
Cyl - 0 - 0.75 Sph equiv |
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Toric lens |
0.75 - 2.00 Transpose rx |
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Gas perm |
+/ - 2.24 |
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For starting trial lens we… |
Sphere equiv |
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For power we… |
Transpose |
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- long eye |
. |
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+ short eye |
. |
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To find HVID |
Add +2 |
