Cylinder lens
A cylinder lens is different than a spherical lens which is what one normally sees in spectacles. Although a cylindrical component my be built in to that which appears spherical.
As can be seen in the above diagram a cylinder lens has power only in one axis. In the above it is the horizontal axis. This lens does not refract light in the vertical direction.
Astigmatism
Visual Acuity
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Subject Index
Table of Contents [When not using frames]