REFRACTIVE INDEX
Characterizes the refractive power of a transparent optical material.
The indices vary according to the materials used for the lenses:
Plastic lens: 1.5
Polycarbonate lens: 1.59
Medium or High Index lens: > 1.5
Trivex™ lens: 1.5 to1.6
Tribrid™ lens: 1.6
Glass lens: 1.5 to1.9
SINGLE VISION LENS
Type of single vision lens correcting amétropies. The power of the lens is the same over all its surface.
SYMMETRIC BINOCULAR TRACING
The shape of the right circle of frame is applied symmetrically to the left circle; the traced perimeters are preserved.
TRIFOCAUX BIFOCAL LENSES/
Type of lens with distinct correction areas:
the upper part of the lens is used for far vision.
the lower part of the lens is used for the near vision.
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