Prisms - Dr. Paul Harris, Optometrist

relatively inexpensive and easy to apply and change in the office. The
one disadvantage is that they do degrade the quality of the image more
than a ground in prism. However, the Fresnel prisms come in powers
above that which can
practically be ground into
standard lenses.
In general, use the least
amount of prism possible
to achieve binocularity. A
combination of cover test,
both objective and subjective as well as fixation
disparity testing is used to
find the least amount of
prism that can do the job.
Figure 5.
Figure 6.
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