Constant force intraocular lens injector

Abstract

An intraocular lens injection device comprises a tubular housing with a passageway extending along its longitudinal axis and a plunger shaft disposed within and moveable along the passageway. The tubular housing and the plunger shaft have frictional engaging features that are configured to produce a varying plunging friction as the plunger is moved along its operating range, to offset changes in the plunging resistance that arise from injecting the IOL into the eye. The variable plunging friction may comprise one or more step changes in unloaded plunging friction, or a curved variation in plunging friction, or both, along at least a portion of the operating range of the plunger shaft. In some embodiments, a slot of varying width in the housing frictionally engages a tab extending transversely from the plunger shaft. In others, a contoured surface on the plunger shaft frictionally engages an orifice in the tubular housing.

Dependencies are inferred from the claim text.