with a discussion of palpebral lenses as well as larger lenses with wide peripheral
curves. The general characteristics, advantages, and disadvantages of each will
be discussed. This will be followed by methods and procedures for selecting
base curve, diameter, optical zone width, peripheral curves, and thickness through
the use of diagnostic lenses, nomograms and charts. Examples and practice exercises
patterns are used to assist in the evaluation of the fit of rigid contact lenses.
How and why this is accomplished is covered in the second half of this section.
We’ll illustrate flourescein patterns of a spherical base curve on a spherical
cornea, and spherical base curves on a toric cornea are presented. Astigmatism
with the rule, against the rule, and oblique will be discussed and observed.
Soft lens evaluation is then covered to include fitting goals and the characteristics
of a good fitting soft lens.
with a presentation of rigid and soft lens verification techniques to include
the use of the measuring hand magnifier, diameter gauge, projector inspection
devices, slit lamp, radiuscope, thickness gauge, lensometer, and profile analyzer.
We’ll see that soft lenses too can be verified through the use of a hand magnifier,
plastic templates, a soft lens analyzer, and the use of a water cell.