Presbyopia Treatments by Mechanism of Action: A New Classification System Based on a Review of the Literature.

Presbyopia, a loss of accommodative ability associated with aging, is a significant cause of vision impairment globally. At the clinical level, it is a frustrating and difficult issue that negatively impacts patients' quality of life. Less appreciated is the fact that loss of accommodative ability and its current treatments methods may present safety concerns, for example, increasing the risk of falls. Therefore, a more complete understanding of treatment options with respect to how they relate to the natural ability of the eye is needed to improve decision making and to aid clinicians in individualizing treatment options. This article reviews the options for expanding functional through focus-a term coined to describe the ability of the eye to see at all distances with minimal latency-by how they vary the refractive power over time, across the visual field, between eyes, or across a range of distances.