Light-adjustable lens: development of in vitro nomograms.
OBJECTIVE
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.
Schwartz
Daniel M
DM
Beckman Vision Center, Department of Ophthalmology, University of California, San Francisco, San Francisco, California, USA.
Sandstedt
Christian A
CA
Chang
Shiao H
SH
Kornfield
Julie A
JA
Grubbs
Robert H
RH
D001251:Astigmatism / Q000628:therapy*; D004867:Equipment Design; D006801:Humans; D006956:Hyperopia / Q000628:therapy*; D007091:Image Processing, Computer-Assisted; D007368:Interferometry / Q000379:methods; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008027:Light; D009216:Myopia / Q000628:therapy*; D049451:Nomograms; D055095:Optics and Photonics / Q000295:instrumentation; D015203:Reproducibility of Results; D012828:Silicones; D014466:Ultraviolet Rays
D012828:Silicones