overall lens diameter
polishing and refinishing lens edges
polishing lens surfaces
blending transition or junction zones
adjusting peripheral curves
flattening intermediate curves
optic zone diameter
the materials and tools necessary to perform in-office modifications
of rigid contact lenses.
Explain special care required when altering rigid contact lenses
Describe at least two techniques which can be used to reduce the diameter
of a rigid contact lens.
- Describe the instruments
used to assess the diameter of a lens
Explain when and how to polish a rigid lens, modify its power and
adjust the peripheral curves
Describe at least three methods of examining the edge of a lens
Describe an ideal contact lens edge
Identify the signs and symptoms associated with thick edges, square
edges, sharp edges, rolled in and rolled out edges, and the office
modification techniques used to make an improved edge.
ability to carry out modifications of rigid contact lenses in the office
provides benefits to the patient as well as to the contact lens practitioner.
It enables the patient to continue their wearing schedule without interruption
and minimizes the necessity for extra visits. Also, the practitioner
may know best exactly which modification is required which may be difficult
to describe to the laboratory. Any subsequent modifications become apparent
and can be done immediately. Further, practitioners who carry out modifications
are better able to evaluate lenses which have been made or which have
to be modified by a laboratory.
the adjustments that can be made to a lens have the effect of loosening
the fit or increasing tear flow between the lens and cornea. Any adjustments
required to tighten the fit of a lens necessitate the fabrication of
a new lens.
modification of rigid lenses may take the forms listed below.
completion of this course, the participant should be able to: