Punctal plugs: the pros and cons for dry eye

Punctal plugs are tiny inserts placed in the tear drainage openings at the inner corner of the eyelid, so that the tears you do make stay on the eye longer instead of draining away. They are quick to fit, reversible, and they can make a genuine difference to someone whose problem is that they simply do not produce enough tears.

They are also oversold. The most careful summary of the evidence, a Cochrane review of 18 trials, concluded that improvements in symptoms and in the dry eye signs usually tested are inconclusive (Ervin 2017). That does not mean plugs do not work. It means the trials have not shown clearly that they do, which is a different and more awkward statement.

The short version: worth considering if your dry eye is aqueous-deficient and lubricants alone are not holding you. Not the first move if your glands are the problem, which is the more common situation.

What they are, and the types

Each eyelid has a punctum, a small opening near the nose that drains tears into the nasolacrimal system. A plug sits in that opening, or a little deeper in the canaliculus behind it, and slows the drainage.

Dissolvable collagen plugs are the trial run. They last somewhere between a few days and a few months depending on the material, then break down on their own. Clinicians use them to answer a simple question: if we keep more tears on this eye, does this person feel better? If the answer is no, nothing permanent has been done.

Silicone plugs sit in the punctum with a small visible head and stay until they are removed or fall out. These are the everyday long-term option, and they can be taken out in seconds if they do not suit.

Intracanalicular plugs sit deeper, out of sight. They avoid the surface irritation a protruding head can cause, but they are harder to retrieve if there is a problem.

The Cochrane review included trials of collagen and silicone plugs, and separately compared acrylic with silicone, intracanalicular with silicone, and upper with lower puncta. In every one of those comparisons the evidence was judged very low-certainty because of a combination of risk of bias and imprecision (Ervin 2017). There is no reliable basis for saying one type outperforms another.

Who they suit, and who they do not

Plugs make mechanical sense in aqueous-deficient dry eye, where the lacrimal gland is not producing enough of the watery layer. Keeping a scarce resource on the surface for longer is a rational response to scarcity. The Cochrane review's inclusion criteria reflect this: it accepted trials in participants diagnosed with aqueous tear deficiency or dry eye syndrome (Ervin 2017).

They make much less sense as a standalone treatment for evaporative dry eye. If your tears are draining away too fast through the front of the eye rather than the back, because the oil layer from the meibomian glands is poor, holding more of a poor-quality tear film on the surface does not fix the leak. It can even feel worse, because you are retaining tears that are inflammatory in a surface that is already irritated. DEWS II treats the two forms as a continuum rather than a clean either-or, with elements of each considered in diagnosis and management (Craig 2017), so the practical question is which side dominates in you. If you are not sure, start with the difference between evaporative and aqueous-deficient dry eye and get it measured rather than guessed, using the standard tests.

One more group to flag: people whose main complaint is watering. Watery eyes are often a dry eye symptom, not the opposite of one, as we explain in why eyes water when they are dry. Blocking drainage in someone who already overflows can make the overflow considerably worse.

What the evidence actually shows

The 2017 Cochrane review pooled 18 trials with 711 participants and 1,249 eyes, from ten countries. The reviewers judged the trials to be at unclear risk of bias overall, because they were poorly reported, and assessed eight separate comparisons.

On the comparison most people care about, plugs versus no plugs, five trials were available. Evidence on symptomatic improvement was very low-certainty, and in all three trials that reported it there was little or no improvement in symptom scores with plugs compared with no plugs. On signs, one trial gave low-certainty evidence of less ocular surface staining with plugs, though the reviewers described the difference as small and possibly clinically unimportant. Tear film stability was slightly better with plugs, by 1.93 seconds. The number of artificial tear applications was lower with plugs, by 2.70 applications. One trial found little or no difference in Schirmer scores.

Against artificial tears, five trials showed very low-certainty evidence on symptoms, low-certainty evidence of little or no improvement in ocular surface staining, and low-certainty evidence of little or no difference in aqueous tear production.

The authors' conclusion is worth quoting in substance: although the investigators of the individual trials concluded that plugs are effective for dry eye signs and symptoms, the review found improvements inconclusive, and the type of plug, the type and severity of dry eye treated, and heterogeneity in trial methods confounded any decisive statement about effectiveness (Ervin 2017). Adding 11 trials to the earlier 2010 review did not change the picture.

Read that carefully. The needing-fewer-drops finding is the most practical one in the review, though it rests on a single trial of 61 eyes and low-certainty evidence. The symptom finding is the disappointing one.

Risks, side effects and what it feels like

Fitting a plug takes a minute or two per eye in the consulting room. There is no cutting and usually no anaesthetic beyond a drop. Most people describe a moment of pressure and nothing more. Some feel a slight awareness at the inner corner for a day or two afterwards, particularly with a silicone plug that has a head sitting at the lid surface.

The Cochrane reviewers rated the adverse event data very low-certainty, but reported that events occurred reasonably frequently in the plug group and included epiphora, itching, tenderness and swelling of the lids with mucous discharge, and plug displacement. Their overall safety statement is that although plugs are believed to be relatively safe, their use is commonly associated with epiphora and, less commonly, with inflammatory conditions such as dacryocystitis (Ervin 2017). Canaliculitis, inflammation of the drainage channel itself, is a recognised complication outside the trial evidence, and is one of the reasons a plug that starts causing discharge or a tender inner corner should be looked at promptly rather than tolerated.

Displacement is the quiet problem. Plugs fall out, often unnoticed. If your symptoms return months later, check the plugs are still there before assuming the treatment failed.

Cost, and why the lids usually come first

Costs vary widely by country and clinic, so figures here would mislead. The general shape: collagen trial plugs are inexpensive and often folded into a consultation, silicone plugs cost more but are a one-off rather than an ongoing spend, and the real variable is how many follow-up visits you need. Ask for the total before you agree.

Most optometrists and ophthalmologists work through the lid margin and the meibomian glands first, and that is not obstruction. DEWS II sets out a staged management algorithm applied step-wise according to severity, and notes that distinguishing aqueous-deficient from evaporative disease is critical in choosing the strategy (Jones 2017). Since gland dysfunction is the more common driver, the first steps are usually warmth, lid hygiene, lubrication and, where indicated, work on unblocking the glands, in the order set out in the daily dry eye routine. Plugs come into their own when that groundwork is done and a genuine aqueous deficit remains. Where the surface is inflamed, prescription anti-inflammatory treatment may enter the conversation too, prescribed and monitored by an ophthalmologist or an optometrist with prescribing rights.

If you have an active eye infection, have had eye surgery recently, have glaucoma, or notice any change in your vision, speak to your optometrist or ophthalmologist before any lid or drainage procedure and while you have plugs in place. Discharge, a tender inner corner or worsening watering after fitting should be reviewed promptly rather than tolerated.

Frequently asked questions

Do punctal plugs actually work for dry eye?

The evidence is weaker than most people expect. A 2017 Cochrane review of 18 trials and 711 participants found that improvements in symptoms and in commonly tested dry eye signs were inconclusive, with very low-certainty evidence on symptoms. One trial of 61 eyes found fewer artificial tear applications with plugs in place, on low-certainty evidence. Individual patients do report benefit, but the trial evidence does not establish it clearly.

Are punctal plugs painful to have fitted?

Not usually. The plug is placed into an opening that already exists, so there is no cutting, and the procedure takes a minute or two per eye with at most an anaesthetic drop. Most people report brief pressure and nothing else. Some awareness at the inner corner for a day or two afterwards is common, particularly with plugs that have a visible head.

What are the main risks of punctal plugs?

The Cochrane review reported that adverse events occurred reasonably frequently in trial plug groups, including watering, itching, tenderness and swollen lids with mucous discharge, and plugs moving out of position. It also noted that plug use is commonly associated with watering and, less commonly, with inflammatory conditions such as dacryocystitis. Any discharge or tenderness at the inner corner should be reviewed promptly.

Will plugs help if my dry eye is from blocked meibomian glands?

Not on their own. Plugs conserve the watery part of the tear film, which addresses a shortage of tears rather than a poor oil layer. If evaporation is the dominant problem, holding more tears on an unstable surface does little and can occasionally feel worse. Most clinicians treat the lid margin and glands first, then reconsider plugs if a genuine tear deficit remains.

Educational information only, not medical advice. References: Ervin AM, et al. Cochrane Database Syst Rev. 2017;6:CD006775; Craig JP, et al. Ocul Surf. 2017;15:276–283; Jones L, et al. Ocul Surf. 2017;15:575–628.