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Introduc.DIr
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00056_Field_56.txt
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1997-10-29
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715b
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25 lines
LENS DESIGN
SAGITTAL DEPTH
Another important concept to
understand with contact lens fitting
is sagittal depth. With a curved
surface of a certain radius and chord
diameter, it will have a given sagittal
depth (see #1) which can be
mathematically determined. One can
think of the sagittal depth of a
contact lens as the distance from a
flat surface the lens is resting on up
to the back surface of the lens.
The steeper the radius, the greater
the sagittal depth (S ) if the chord
diameter is not changed (see #2).
If the radius of a curve is not changed
but the chord is made larger, the
sagittal depth (S ) will be greater
(see #3).