Staying Plugged in on Lacrimal Occlusive Devices:
a Review of Indications and Complications
By Clara C. Chan, MD, FRCSC, FACS, and Jeffrey J. Hurwitz, MD, FRCSC
Punctal and canalicular plugs enhance the eye’s tear film by blocking lacrimal drainage. They are used principally in the management of dry eye disease but can be helpful in other conditions that cause eye dryness. While generally safe, plugs are relatively contraindicated in dry eyes with coexisting untreated inflammation as blockage of the puncta exposes the ocular surface to cytokines, which can worsen ocular inflammation and patient symptoms. Clinicians should also be aware of the complications that have been reported with different plugs. This issue of Ophthalmology Rounds provides an overview of the punctal and canalicular plug options and the associated benefits and risks with this procedure.
A number of punctal and canalicular plugs are available to ophthalmologists. Plugs can be classified according to their location and duration of action as well as whether they are serving to provide complete or partial occlusion (Figure 1). Punctal plugs are visible at the punctal opening and may be removed easily. They are made of a variety of materials and have different characteristics (Table 1). In contrast, canalicular plugs are placed either inside the vertical or horizontal canaliculus. Extrusion risk is reduced but there is increased risk for migration.
Figure 1: Classification of lacrimal occlusive devices
Table 1: Punctal plugs: design features and details
Indications of Punctal and Canalicular Plugs
Dry eye disease
The international Dry Eye WorkShop (DEWS) defined dry eye as a multifactorial disease of tears and ocular surface with symptoms of visual disturbance, discomfort, and tear film instability with associated ocular inflammation and increased tear film osmolarity. The DEWS classified dry eye disease into 4 levels depending on severity of the disease and treatment options were recommended accordingly. Topical lubricants, topical cyclosporine, tetracyclines, and punctal plugs were a few of the available treatment options mentioned.
A Canadian consensus paper, developed from a meeting of a panel of Canadian cornea and external disease subspecialists, similarly presented a staged treatment algorithm for dry eye disease.
Lifestyle modifications, regular hygiene, and tear supplements may be sufficient in patients with mild symptoms
Anti-inflammatory medications (topical cyclosporine A, short courses of topical steroids, Ω-3 fatty acid and flaxseed supplementation, and/or oral tetracyclines) and physical measures (punctal plugs, moisture-retaining eyewear) are implemented for those with moderate-to-severe symptoms
Autologous serum tears, scleral contact lenses, and tarsorrhaphy are reserved for patients with severe symptoms who have an unsatisfactory response to anti-inflammatory medications
Patients with coexisting lid disease, meibomian gland dysfunction, rosacea, and allergic eye disease should be identified and receive therapy to address those underlying etiologies for their dry eye symptoms. Patients with partial blinking or who engage in long durations of screen time need to be reminded to increase their full blink rate. Structural abnormalities like conjunctival chalasis, lagophthalmos, lid laxity, entropion, or ectropion may also need to be addressed surgically. Corneal “lumps and bumps” such as pterygia, Saltzman nodules, and epithelial basement membrane degeneration need to be properly identified and surgically managed as well. The clinician should be aware that plugs are relatively contraindicated in dry eyes with coexisting untreated inflammation as blockage of the puncta exposes the ocular surface to cytokines which can worsen ocular inflammation and patient symptoms. It is recommended that the quality of the tear film be optimized first with anti-inflammatory therapy over the course of a few months prior to the insertion of punctal plugs. In addition, nasolacrimal duct irrigation should be performed to ascertain whether their placement will provide benefit. To avoid the risk of epiphora, the lower puncta should be plugged first.
A 2017 Cochrane review noted that the investigators of the 18 trials (N=711) included in the review concluded that punctal plugs are effective in the treatment of dry eye signs and symptoms; however, the reviewers found that these improvements were inconclusive due to the heterogeneity in trial methodology. In a literature review for the American Academy of Ophthalmology (AAO), Marcet et al concluded that lacrimal drainage system plugs – punctual, intracanalicular, and dissolving – were effective and well tolerated in the management of the signs and symptoms of moderate dry eye that does not respond to topical lubrication.
Few comparative studies have been conducted between types of punctal plugs. A recent randomized controlled trial of 50 eyes with moderate to severe dry eye comparing 2 types of punctal plugs found that retention rate was significantly better at 6 months in the Parasol® (Odyssey Medical, Memphis Tennessee; Beaver Visitec International, Waltham, Massachusetts) group versus Superflex® plugs (Eagle Vision, Memphis, Tennessee, Softplug-Oasis Medical Inc., Glendora, California) (68% vs 32%; P=0.024). There was also a statistically significant improvement in all secondary outcome measures (Schirmer I test, tear meniscus height, tear break-up time, fluorescein corneal staining) at 6 months within plug groups and no plug complications were reported. Further comparative studies are needed to draw definitive conclusions regarding differences between various types of plugs.
It is very common for patients to experience transient dry eye symptoms after laser vision correction. One study reported an incidence of 59% at 1 month after laser in situ keratomileusis (LASIK). Thus, lacrimal plugs have a role in post-refractive surgery dry eye management, and preoperative use may be considered in higher-risk patients (ie, peri- or postmenopausal women); however, preoperative lacrimal plugs are controversial as occlusion reduces the clearance of tears which can worsen the dryness associated with increasing proinflammatory cytokines.
A prospective randomized trial evaluated the use of punctal plugs after LASIK for prevention of dry eye in 78 eyes of 39 patients. Subjects underwent bilateral LASIK, and lower punctal occlusion of one eye was performed while the other eye served as a control. The ocular surface index score was better at all follow-up visits, and improvement was statistically significant for eyes with punctal plugs compared to the control eyes. At the 6-month postoperative final visit, although there was no statistically significant difference between the 2 eyes, the Schirmer I test, tear breakup time, and punctate epithelial keratitis scores were better in the punctal plug occluded eyes than the control eyes.
In a retrospective study of 21 eyes of 12 patients, patients with post-refractive surgery low refractive errors noted improvement in their vision at 1 month after silicone punctal plug placement. Eighty-six percent of eyes (18 of 21) gained at least 1 line of Snellen uncorrected visual acuity after punctal plug placement, and only 8% of patients (1 of 12) pursued refractive surgery enhancement after punctal plug placement. One patient experienced plug extrusion in both eyes and none requested plug removal. Collagen canalicular plugs can last from 3–14 days and thus can be used for short-term improvement of symptoms of dry eye after laser refractive surgery; however, the temporary-extended duration type of vertical canalicular plug that last about 3 months are likely to be more reliable in its ability to provide full occlusion. In a prospective, comparative, nonrandomized study, Huang at al reported statistically significant improvement in higher-order wavefront aberrations after 1 month of temporary punctal occlusion in 16 eyes of 8 patients with post-LASIK dry eye compared to 10 eyes of post-LASIK patients without dry eye.
Contact lens wear
Contact lens wearers with symptoms of dry eyes can benefit from punctal and canalicular plugs. Increased tear retention improves the symptoms of dry eye. In a study with contact lens wearing patients with and without dry eye symptoms (20 eyes in each group), 1 eye was randomized to both upper and lower collagen punctal plug occlusion followed by ultrahigh-resolution optical coherence tomography to image the tear menisci. Menisci were increased transiently in both symptomatic and asymptomatic lens wearers and increased for a longer duration in symptomatic wearers (4 days versus 1 day). Comfort scores were directly correlated with tear volumes. Another study involved the monocular insertion of silicone punctal plugs in the lower puncta of 25 contact lens wearers with dry eye symptoms. At the 3-week follow-up visit, 18 of the 25 patients reported an increase (average 34.6%) in comfortable contact lens wear time.
It is important to note that the approach to managing a patient with contact lens intolerance due to dry eye symptoms should be the same as a dry eye patient without contact lenses as described in the earlier section on dry eye. Patients should be counselled that if discomfort persists with contact lens wear that they need to discontinue wear to prevent irreversible damage to their corneas.
Acquired punctal stenosis
Epiphora secondary to punctal stenosis has been reported, emphasizing the need to place temporary punctal plugs or to have patients to occlude the lower punctum for at least 5 minutes after instilling topical mitomycin for the treatment of ocular surface squamous neoplasia. Occluding the punctum is also important to minimize adverse changes in the nasopharyngeal epithelium with topical mitomycin. Scarring of the lacrimal drainage apparatus reported with systemic fluorouracil (5-FU) for colon and breast cancer treatment has not been found with topical administration. Ideally, both upper and lower puncta could be occluded in the above clinical scenarios. Interferon-a2b for ocular surface neoplasia requires a more prolonged treatment course but has few adverse effects and minimal risk for limbal stem cell deficiency and scarring of the lacrimal drainage apparatus.
Perforated silicone punctal plugs coated in polyvinylpyrrolidone have been reported to treat complete and partial punctal stenosis but are controversial. In a study of 44 eyes of 26 patients, lid laxity was found in 14 of the eyes but just 8 eyes underwent lateral tarsal strip procedure prior to perforated plug insertion. The plugs were removed after 2 months with an average of 19 months of follow-up. Relief of epiphora was achieved in 84.1% of eyes although 3 eyes had recurrence and 4 eyes had mild horizontal lid laxity. Another retrospective study with more than 6 months of follow-up involving 20 eyes of 20 patients who had a 2-month course of perforated punctal plug insertion found similar results. Epiphora resolved in 85% patients and those who failed were older and more likely to have associated blepharitis. Wound healing was found to have occurred around the perforated punctal plug, which prevented restenosis. In clinical practice, adequate punctal dilation can usually enlarge the puncta sufficiently in patients with punctal stenosis. Failing that, a simple snip punctoplasty is very effective without having the potential risks of a foreign body.
Superior limbic keratoconjunctivitis (SLK)
The pathophysiology for superior limbic keratoconjunctivitis involves rubbing of the upper lid and superior limbus and irritation from that friction due to localized tear deficiency. A study of 22 eyes with SLK in which upper punctal occlusion was performed found improvement of symptoms and reduced rose Bengal and fluorescein staining in all eyes. Impression cytology also found improvement in squamous metaplasia in the superior conjunctival area and increased goblet cell density in 69% of eyes. The use of plugs in patients with SLK is certainly worth attempting prior to proceeding with surgical treatment involving superior conjunctival resection and reconstruction using tissue glue.
A large retrospective study of 203 eyes of 153 patients with arrow-shaft silicone punctal plug insertion found that 11% of the eyes had plugs for SLK as the indication. Other reported indications in the study included dry eye syndrome (62.5% eyes), epitheliopathy after penetrating keratoplasty (15.8% eyes), neurotrophic keratitis (4.4% eyes), recurrent corneal erosions and ocular cicatricial pemphigoid (3% eyes each), persistent epithelial defect (2.4% eyes), and toxic epitheliopathy not controlled by lubrication with preservative-free tears (1.5% eyes). Study results at 4±2 weeks of follow-up indicated significant improvement in patient symptoms in 73.9% of eyes, decreased corneal fluorescein staining score (from mean 2.7 to 1.3), and decreased frequency of lubrication.
We now have a better understanding of the negative effects of ocular-surface toxicity from glaucoma topical medications and associated preservatives such as benzalkonium chloride. Various sustained release depots of preservative-free medications in the form of a punctal plugs are being studied for glaucoma therapy. A Phase II study on a sustained-release formulation of preservative-free latanoprost delivered through a nonabsorbable punctal plug has demonstrated a statistically significant reduction in intraocular pressure (IOP; 5 mmHg) at various time points from 30–90 days with the 95-µg plug in the upper punctum. Plug retention was 69%–76% at 4 weeks, 53%–65% at 8 weeks, and 48%–58% at 12 weeks. The main side effects reported were eye itching and tearing. Phase III studies are being planned. An absorbable preservative-free travoprost intracanalicular plug is also being studied. A polyethylene glycol (PEG) hydrogel casing stained with fluorescein allows for sustained drug release over 3 months. The insert expands in the canaliculus and remains visible through the eyelid using a slit lamp with a yellow filter and blue light. The clinician can track plug retention and position throughout the treatment period, and as the plug degrades it flushes through the system and removal is not required. In a Phase II study, 65 patients with the travoprost plug had mean IOP maintained between 19.2 and 22.2 mm Hg at all time points through Day 75 and 90 with mean IOP reductions from baseline ranging from 2 mm Hg (9%) to 6 mm Hg (24%). The study also reported Kaplan-Meier estimated median time to absence of the insert to be about 70 days, reflecting insert absorption. No serious adverse events were reported but 2 subjects discontinued study participation due to an adverse event and types of adverse events reported were inflammatory reaction, dacryocanaliculitis, acquired dacryostenosis, eyelid edema, and lacrimal structure injury.
Patients who have allergies to any of the materials used to make punctal plugs should not use the device. If a patient already has outflow obstruction issues then punctal plugs should not be used. Other strict contraindications include active ocular infection and untreated ocular surface and lid inflammation such as blepharitis. The insertion of punctal plugs would prevent the outflow of infective organisms and proinflammatory cytokines, respectively, leading to exacerbation of patient symptoms.
Safety and Efficacy
In 2015, the AAO Ophthalmic Technology Assessment Report was published on the subject of safety and efficacy of lacrimal drainage system plugs for dry eye syndrome. The inclusion criteria for the review were met by 27 studies representing level 2 and 3 evidence (original data on plugs for the treatment of dry eye in at least 25 patients); there were no level 1 randomized control trials. Plugs examined in the studies included punctal, intracanalicular, and dissolving types. Plug placement resulted in ≥50% improvement of symptoms, improvement in ocular-surface health, reduction in artificial tear use, and improved contact lens comfort in patients with dry eye. With respect to complications, plug loss was the most commonly reported problem occurring on average in 40% of patients. Overall, among all plug types, approximately 9% of patients experienced epiphora and 10% required removal because of irritation from the plugs. Canaliculitis was the most commonly reported problem for intracanalicular plugs and occurred in approximately 8% of patients. Other complications were reported in less than 4% of patients on average and included tearing, discomfort, pyogenic granuloma, and dacryocystitis. A complete list of complications is listed in Table 2.
Management of Complications
Tearing from plug migration ± obstruction
In the event of tearing after a punctal or canalicular plug insertion, the clinician must first diagnose if the plug is still in the lacrimal system, whether it has fallen out, or is still somewhere in the canalicular system. A lack of visibility at the punctal site indicates that the plug has fallen out or that it has migrated down the canalicular system. It is important to know what kind of plug was inserted and which of the puncta and/or canaliculi had plugs. If both upper and lower have been plugged, removing just one may decrease the tearing and still allow for control of dry eye symptoms.
Irrigating the lacrimal system will reveal an obstruction if the plug is still in the system, and the distance from the punctum to the obstruction should be measured. If the plug has migrated down the system, it usually gets stuck at the junction between the canaliculus and common canaliculus, where the proximal canaliculus narrows. An obstruction palpated with the cannula may be due to scarring caused by the plug (either permanent or dissolvable) further to plug dislodgement or from obstruction with the plug still in the canaliculus. More sophisticated investigations may help with the diagnosis such as by dacryocystogram to show an obstruction caused by the plug (Figure 2) or with ultrasound biomicroscopy to determine if the plug is present in the canaliculus (Figures 3A,3B).
In the management of plug complications, it must be determined whether a wet eye is preferable to a dry eye that might develop if the plug is removed. The patient may prefer the wet eye and opt to do nothing. Although it has been suggested to try to push the embedded plug with a probe through to the nose, this is probably not a good idea, as this blind procedure has a real chance of damaging the canalicular mucosa where the plug has lodged. If the plug is stuck in the proximal canaliculus, a “snip” (1, 2, or 3 snip) can be made in the punctum, and the plug extracted with small-toothed forceps. If the plug is stuck further down at the canaliculus-common canalicular junction, a full dacryocystorhinostomy with exploration of the common canaliculus is usually necessary to remove the plug.
Canaliculitis with or without a coexisting “pyogenic granuloma” can occur with both permanent and temporary plugs. Discharge becomes the main symptom, and plug insertion may have been something in the distant past. There may be a swelling over the canaliculus, with a pouting punctum, and discharge coming out of the punctum (Figure 4). Hot compresses and topical (and sometimes systemic) antibiotics are usually helpful. The clinician should dilate the punctum widely, and often stones (± the plug) can be expressed. If this does not work, a “snip” punctoplasty (canaliculotomy) can be performed, and the stones (± the plug, ± a pyogenic granuloma) curetted out.
Dacryocystitis has been reported, but this situation must be extremely rare, as it is improbable that the small plug would block the sac-duct junction.
Loss of plug
In cases where a plug has been lost, tear flow may still be decreased and symptoms controlled if some residual stenosis remains in the system. In these cases, it may be better not to reinsert the plug. It is important, as has been mentioned, to irrigate the duct before considering reinsertion, as the system may indeed be blocked or stenotic.
A wide variety of punctal and canalicular plugs are available. The AAO Ophthalmic Technology Assessment Report concluded with the following major points:
Punctal plugs are generally effective in improving the signs and symptoms of moderate dry eye that persists despite the application of topical lubrication
Permanent plugs may be more efficacious than dissolving plugs
Intracanalicular plugs may not be the optimal lacrimal plug option compared with other available modalities further to the potentially greater risk of canaliculitis and pyogenic granulomas, which potentially require more invasive treatments such as canaliculotomy and dacryocystorhinostomy in a minority of patients
Higher rates of epiphora and plug loss were associated with punctal than intracanalicular plugs
While dry eye therapy is the major indication for the use of plugs, they play an important role in the prevention of punctal stenosis in patients with ocular surface squamous neoplasia who require topical mitomycin or 5-FU therapy. Perforated punctal plugs, while controversial, have been reportedly used for patients with punctal stenosis to treat epiphora. In the near future, punctal plugs may serve as a means for the sustained release of a variety of medications. Ophthalmologists should be aware of the limitations and risks associated with the placement of plugs and patients should be monitored closely.
Dr. Chan is Medical Director of the Eye Bank of Canada (Ontario Division), and Assistant Professor, Department of Ophthalmology & Vision Sciences, University of Toronto; UHN - Toronto Western Hospital, St. Michael's Hospital, and Kensington Eye Institute, Toronto, Ontario. Dr. Hurwitz is Professor, Past Chair, and Vice Chair, Global Health, Department of Ophthalmology & Vision Sciences, University of Toronto, and Mount Sinai Hospital.
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Disclosures: Dr. Chan has previously received honoraria from Alcon Labs Inc, Allergan, Bausch + Lomb, Santen, Shire, and Tearscience; and research grant funding from Allergan, Bausch + Lomb, and TearLab. Dr. Hurwitz stated that he has no disclosures to report in association with the contents of this issue.
Table 2: Complications of punctal and intracanalicular plugs
Figure 2: Dacryocystogram showing complete obstruction at the lateral common canaliculus due to a stuck, migrated punctal plug
Figures 3A,3B: Ultrasound biomicroscopy of an intracanalicular plug (3A), and the same plug within the horizontal lower canaliculus (3B), as identified by the hash marks.
Figure 4: Patient with upper canaliculitis a few years after plug insertion
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