Punctal Plugs and Intracanalicular Plugs
An introduction to plugs including concepts, materials, designs, duration.
Introduction to plugs
What they are, how they are used, the variety of plugs available, and why patients should be involved in all decisions about plugs.
Understanding different types of plugs
We discuss differences between plugs in terms of location of placement; material; design; and placement.
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Talk about plugs
Check out our Plug forums, on Dry Eye Talk for archives of discussions about punctal plugs.
What are they? Small plugs placed in the corners of the eyes to reduce tear drainage.
How are they used? After artificial tears, punctal occlusion with plugs is one of the most common forms of treatment for chronic dry eye. The most typical usage of plugs is in the lower two puncta, but some people have plugs in all four ducts (two lower, two upper).
Be aware - all plugs are not equal! There are a great many types of plugs and for any given individual some may perform better than others, or be more comfortable, or last longer. In addition, the risks of plugs will vary depending on material and where they are inserted. See below for more information.
Caution advised. Finally, while plugs are a common treatment, it is an invasive treatment and carries risks. It is very important that you discuss with your doctor all your treatment options and if you decide to try plugs, make sure to discuss the specific plug options and the relative risks and benefits. We strongly encourage use of a written "Informed Consent" that you can take home, consider, and discuss with your doctor before undergoing the procedure. We have heard of patients being plugged without even being told (let alone asked) and feel that this should not be done.
For more general information: Please see our punctal occlusion page for further information including what plugging is all about and what it's like to 'get plugged' from the patient's perspective. Also visit our punctal occlusion forums on the bulletin board for real patients' experiences.
Punctal plugs fall into one of two groups:
- Punctal (or punctum) plugs, which are placed at the tops of the puncta. The tops of these plugs are often visible to the patient looking carefully in a mirror. Generally speaking, the advantage of punctal plugs is ease of removal, with the accompanying disadvantage that they may more easily lost.
- Intracanalicular plugs, which are inserted into the canalicula. Most plugs of this type cannot be seen after insertion. They cannot be removed in the way punctal plugs can, though they may be flushed out with irrigation.
In practice often all types of plugs collectively are referred to as punctal plugs. Both types of plugs may cause some slight discomfort, especially when turning the head all the way to one side. If a punctal plug is too loose,
- "Temporary" plugs are usually made of collagen and are designed to last long enough to determine whether a patient can benefit from plugging.
- Extended duration temporary plugs are typically made of synthetics such as PCL.
- Punctal plugs are generally made of silicone.
- Intracanalicular plugs are now available made from several different materials. Silicone plugs remain popular, although there are thought to be some risks of them migrating in places they shouldn't go, particularly if there is an attempt to irrigate them out. More recent entrants include the SmartPlug, which is made of a
thermodynamic acrylic polymer so that it can conform to the space it's in, and the Oasis FormFit plug, which is made of a hydrogel (thought to carry lower risk if it has to be irrigated out).
For such a teeny bit of material there is a surprising range of shape designs for plugs, in terms of the shaft, cap (if punctal), and overall concept.
Some noteworthy innovative designs include:
- Smartplugs, which change shape when warmed up to body temperature and become shorter/fatter to fill the space;
- Oasis FormFit plugs, which hydrate after insertion and expand to fill the space; and
- Eagle "Flow Controller" plug and FCI "Perforated" plug, designed for people who experience overflow (epiphora) if full occluded
The range of sizes available for a given plug varies considerably. In general sizes range from 0.2mm diameter to over 1mm but the majority of plugs are avaiable in the 0.3 to 0.5 or 0.6 range.
Duration: "permanent" versus "temporary"
Editorial comment: When you hear that a type of plug is "permanent", don't believe it. While clearly there are plenty of people who have been happily plugged for years with the same pair, I really don't believe in "permanent" plugging. The medical literature does not appear to support the idea that plugs can be expected to last permanently, and in fact many of the studies entirely fail to address plug loss rates (whether falling out the front or flushing through the other end).
So, in terms of duration, I would be tempted to place plugs in one of three classes:
- Group 1: "QUICK TRIAL": Days; rarely, weeks: This would be the collagen plugs which are often used to determine whether someone would benefit from plugs at all.
- Group 2: "SHORT TERM": Weeks, maybe months: This is the increasingly popular synthetics / "absorbables" that are expected to last up to 3 months, or 3-6 months. This is maybe a good choice for people not enamoured of the risks of silicone plugs and who have money to burn, or who aren't sure they need long-term plugs, or who have seasonal dryness, or... you get the idea.
- Group 3: "LONG TERM - IF I'M LUCKY" At this price, you'd better hope they last at least 6 months! This would include all the plugs where they don't say how long they last, or call them long-term.