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Updated: Aug 19, 2026
Development of an In Vitro Ocular Platform to Test Contact Lenses
Published on: April 6, 2016
Light-adjustable lens: development of in vitro nomograms
Daniel M Schwartz1, Christian A Sandstedt, Shiao H Chang
1Beckman Vision Center, Department of Ophthalmology, University of California, San Francisco, San Francisco, California, USA.
Purpose:
To determine whether digital spatial intensity patterns can be developed to effect precise in vitro correction of myopic, hyperopic, and astigmatic refractive errors in a silicone light-adjustable lens (LAL). Also, to determine whether a new spatial intensity pattern for "lock-in" is effective in vitro.
Methods:
A digital interferometer/irradiation system was developed to irradiate LALs and measure the power change following irradiation. Light-adjustable lenses were mounted into a wet cell maintained at 35.0 +/- 0.5 degrees C (simulated ocular temperature) and allowed to equilibrate for a minimum of 2 hours. Ultraviolet light was then applied with spatial light intensity patterns to correct hyperopia, myopia, and astigmatism. Light-adjustable lenses were also treated to effect lock-in with a separate spatial light intensity pattern. Treated lenses were characterized for power change and optical quality. In the case of lock-in, exhaustive chemical extraction was also performed to determine the percentage of remaining macromer.
Results:
Appropriate digital irradiation spatial intensity patterns were created to develop nomograms for in vitro correction of myopia, hyperopia, and astigmatism in approximate 0.25 D steps. Power changes were reproducible and did not alter optical quality of the LALs. Further, lock-in dosing of the LALs did not alter optical quality or significantly change LAL power.
Conclusions:
In vitro nomograms have been developed for a silicone LAL that permit precise correction of myopia, hyperopia, and astigmatism. Furthermore, a spatial light intensity pattern has been devised that effects lock-in without significantly altering LAL power or optical quality.
