Abstract
The accurate measurement of hydrogel contact lenses presentsa number of problems. The inherent flexibility of the material and its similarity to saline, in terms of
refractive index, make measurements unpredictable and difficult.
The aim of the experimental work was to develop an accurate
method for measuring the radii of curvature, thickness and
refractive index of hydrogel contact lenses. The construction
of novel apparatus allowed interference patterns to be
generated using a Linnik micro-interferometer. The generated
patterns were analysed and the radii of curvature of a series
of Bausch and Lomb SOFLENSES were calculated to an accuracy
of 10-3 mm. The experimental results showed a good agreement
with the theoretical results published by the manufacturer.
The micro-interferometer was also employed to determine the
refractive index of a range of hydrogel materials.
The spherical aberration of SOFLENSES in air and in situ on
the human eye was investigated using a commercially available
photoelectric keratoscope, the "PEK" system 2000. The results
present a comprehensive view of the changes in the lens
parameters when applied to the cornea.
| Date of Award | Sept 1979 |
|---|---|
| Original language | English |
| Awarding Institution |
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Keywords
- optical considerations
- synthetic hydrogel polymers
- contact lens usage