Purpose : Presbyopic subjects are not able to accommodate to near objects but they usually exhibit almost intact convergence and near pupil responses capabilities. We wanted to capitalize on these facts to demonstrate the viability of a device where the optical power of optoelectronic lenses was automatically driven by the size of subject’s pupils.
Methods : We designed and built a binocular open-view instrument comprised of two optoelectronic lenses, a pupil-meter and tracking system and visual stimuli presented at different distances. The high-speed eye pupil tracking system was implemented on a GPGPU (General-Purpose Graphics Processing Unit) that is capable of operating up to 500 Hz, providing information of the position and size of the pupil. Two optoelectronic lenses were placed in front of the eyes allowing to change the optical power in a controlled way as function of the applied voltage. Two presbyopic subjects participated in the study. A calibration procedure was required to match the changes in pupil size for different object vergences with the values of added power by the lenses. The refractive range was also adjusted to render images at focus from 3 m to 25 cm.
Results : The system provided real time focussed images for objects placed at all distances in presbyopic subjects under controlled experimental conditions. In addition to the perceived experience by the subjects, series of pupil and lenses responses for natural viewing demonstrated the viability of the approach. The correction speed was faster when subjects accommodated from far to near than the opposite due to the different temporal behaviour of the pupil response. The use of pupil position, related to convergence, in addition to pupil size could render the system more robust for possible ambient luminance changes.
Conclusions : We demonstrated the potential of using geometrical characteristics of the pupil to drive optoelectronic lenses automatically. Presbyopic subjects had images of objects placed at different distances at focus automatically when they simply changed fixation under natural binocular viewing.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.