Abstract
Purpose :
The common option for correcting near vision for presbyopic emmetropes is using single vision ophthalmic lenses, which correct vision for a specific distance. Thus, different pairs of glasses are required for different viewing distances. We describe electrically tunable lenses that can dynamically adjust to different optical powers, that can be used for dynamic focal glasses. When the lens is turned off, it has no optical function, and when it is turned on it can be tuned to any relevant optical power. The electronic lenses are based on Liquid Crystal technology, with no mechanical moving parts. This study compared the power diopter obtained from liquid crystal lenses as measured by mechanical (manual) lensometer measurements.
Methods :
Six lenses were created using a thin layer of Liquid crystal materials (birefringent) placed between two glass substrates with transparent conductors that enable control of the voltage applied upon the Liquid crystal layer. The lenses were activated to obtain a specific power between 0 and 2.5 diopters (in steps of 0.25 diopters and calibration of the lensometer for a measurement sensitivity of 0.125 diopters) in 6 lenses and measured the obtained power using a manual lensometer (TOPCON LM-S1). Repeated Measures ANOVA was used to assess the similarity between the lenses for each power. Pearson correlation was used to assess the correlation between the power settings and the power measured in the liquid crystal lenses.
Results :
The six lenses gave similar readings for each power setting, with no statistical differences between them (f=1.99, p=0.092). There was a significant correlation between the power settings and the average measured power (R=0.99, p<0.0001). The difference between the set and measured power was 0.18 ± 0.07 D, and ≤0.25 D at all settings.
Conclusions :
The liquid crystal lenses exhibit similar diopter power to one another at each of the settings between 0.00-2.50 D. The measured power was similar to the set power. The difference was not likely to be clinically significant. This suggests that the liquid crystal lenses could be used to create dynamic focusing glasses for presbyopia.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.