Lacrimal implants (300) providingsecure retention within the lacrimal punctumof an eye are described. The lacrimal implantscan comprise a implant body (302) configuredfor at least partial insertion through the lacrimalpunctum and into a lacrimal canaliculus. Theimplant body can include a deformable retentionstructure (308) that can be configured tosubstantially encapsulate an expandable retentionelement. In some examples, the expandableretention element can include a fluid absorbingmaterial, which can be exposed to fluid such asvia a fluid permeable retainer or a fluid permeableaperture (320). As the fluid absorbing materialretains fluid (i.e., upon acceptance of fluidinto the retention structure), its size increasesand its shape can change to urge one or moreportions of the retention structure outward, suchas against a wall of the lacrimal canaliculus,thereby securely retaining the lacrimal implantwithin the punctum.
