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. Author manuscript; available in PMC: 2022 May 1.
Published in final edited form as: Prog Retin Eye Res. 2020 Sep 4;82:100901. doi: 10.1016/j.preteyeres.2020.100901

Figure 8.

Figure 8.

Punctal plug innovations for drug delivery. Punctal plugs can be either permanent (for dry eye) or temporary (for drug delivery). Common structural features, which can vary between different plugs, are the core (polymer matrix or drug matrix permeable to tear fluid), cap (semi- or im- permeable membrane with one or more pores), body (impermeable to drug and tear fluid) and nose (assists the insertion process). Plugs come in a variety of shapes and sizes. Some even change shape after insertion due to polymer activation at body temperature.