US Patent 9298021 Methods and lenses for alleviating asthenopia

The invention provides methods and lenses for reducing asthenopia related symptoms associated with proprioceptive disparity. In certain aspects, lenses of the invention include a distance portion and a near portion, and a progressive increase in minus power from the distance portion to the near portion. Additionally, lenses of the invention may include a prism and a progressive reduction in optical power, in which the prism and the progressive reduction are varied independently. In one embodiment, a lens is provided that has a base-in prism and that provides an increase in minus power from the distance vision portion of the lens to a near vision portion of the lens (i.e., a progressive reduction).