  Corneal inlays (CIs) are the most recent surgical procedure for the treatment
of presbyopia in patients who want complete independence from the use of
glasses or contact lenses. Although refractive surgery in presbyopic patients
is mostly performed in combination with cataract surgery, when the implantation
of an intraocular lens is not necessary, the option of CIs has the advantage of
being minimally invasive. Current designs of CIs are, either: small aperture
devices, or refractive devices, however, both methods do not have good
performance simultaneously at intermediate and near distances in eyes that are
unable to accommodate. In the present study, we propose the first design of a
trifocal CI, allowing good vision, at the same time, at far, intermediate and
near vision in presbyopic eyes. We first demonstrate the good performance of
the new inlay in comparison with a commercially available CI by using optical
design software. We next confirm experimentally the image forming capabilities
of our proposal employing an adaptive optics based optical simulator. This new
design also has a number of parameters that can be varied to make personalized
trifocal CI, opening up a new avenue for the treatment of presbyopia.
