Punctal and intra-canalicular occlusion

- a guide for the practitioner -

N.A. Simon Barnard
Department of Optometry & Visual Science
City University
London, UK


The British College of Optometrists (1995) has recently resolved that, in the UK, the use of punctum plugs should be considered as part of normal optometric practice. In this article, punctal and intra-canalicular occlusion are reviewed, and some guidance is given on the use of these products.

The group of conditions loosely called "dry eye" is commonly encountered in optometric practice with patients complaining of symptoms such as a feeling of dryness, a gritty or foreign body sensation and paradoxically, watering eyes. The latter arguably occurs because the lacrimal gland is stimulated by the discomfort caused by a deficiency of "background" tears produced by the glands of the conjunctiva and eye lids.

The causes of "dry eye" are many and complex, and it is not possible in this short paper to review the various aetiologies or methods of diagnosis. However, punctum and intracanalicular occlusion are only appropriate for certain patients with aqueous abnormalities, and it is important that a correct diagnosis is made to allow selection of suitable patients for the procedure.

For example, a common cause of tear lipid deficiency is meibomian gland dysfunction secondary to staphylococcal blepharitis. The bacteria produce enzymes which break down the lipid surface of the tears. When examined with the slit lamp biomicroscope there may be a fast tear break up time together with superficial punctate epithelial staining inferiorly, particularly in the 4 and 8 o'clock positions as well as corneal infiltrates. The use of plugs in such a case would be inappropriate and contraindicated because a possible contributory cause of the dry eye is a bacterial infection which requires treatment. On the other hand, for example, in keratoconjunctivitis sicca associated with Sjögren's syndrome (dry eye, dry mouth and arthritis) there may be a band of corneal and conjunctival staining with Rose Bengal and fluorescein in the absence of lid margin disease. The use of plugs may be indicated in such a case.

The practitioner should therefore obtain an understanding of the differential diagnoses and management/treatment strategies for the various tear anomalies encountered in practice before incorporating punctum or intracanalicular occlusion techniques into routine practice. For a review of tear anomalies and their management the reader is referred to Catania (1995).

Permanent closure of a punctum can be carried out by injuring the tissue to produce scarring. Beetham (1935) introduced surgical occlusion of the punctum using electrocautery as a therapy for aqueous tear deficiency. Other methods include electrodessication or simple excision. Cautery and electrodessication produce tissue destruction with minimal bleeding. Argon laser may also be used to produce precisely positioned burns. Somewhat surprisingly, the occlusion produced by all of these techniques may not last indefinitely, with re-canalisation sometimes occurring (Turberville et al, 1990).

In 1961 Foulds described temporary canalicular occlusion with dissolvable gelatin implants as a prognostic procedure prior to surgical occlusion of the puncta, and in 1975 Freeman described a punctum plug for prolonged but easily reversible occlusion of the puncta.

Effects of occlusion

There have been a number of studies to examine the effects of occlusion.

In patients with keratoconjunctivitis sicca punctal occlusion reduces corneal surface staining (Turberville et al, 1982 and Willis et al, 1987). It may be that this decrease in ocular surface disease was due to a decrease in tear osmolarity (Dohlman, 1978), a hypothesis subsequently supported by the findings of Gilbard (1985).

In a retrospective examination of the effect of punctal occlusion on dry eye disorders using Freeman silicone plug insertion, a significant decrease in tear osmolarity was found together with a reduction in rose bengal staining in 75% of the eyes examined (Gilbard et al, 1989).

Willis et al (1987) occluded all four puncta of eighteen patients (fourteen women and four men) with aqueous-deficient dry eye who were unhappy with their treatment. The patients ranged in age from 26 to 83 years (median age 59 years). Two patients had rheumatoid arthritis, two had reduced unilateral tearing following resection of an acoustic neuroma, and the remainder had keratoconjunctivitis sicca. Four of the patients extruded plugs from the punctum within two weeks of insertion, but all four reported improvements in symptoms until the plugs extruded. Eleven of the fourteen patients (79%) who retained plugs improved subjectively. All were able to reduce their dependency on topical therapy but not cease it completely. Abnormalities in impression cytology persisted 6 weeks after plug placement for each of these eleven patients. The patients reported an additional benefit. Even allowing for the cost of the punctum plugs, the reduced dependency on artificial tears produced considerable financial savings for these patients.

Thirty-five patients with chronic dry eye were treated with Freeman punctum plugs by Fayet et al (1990) . This excellent study was particularly interesting in that whilst occlusion was only carried out unilaterally, the fellow eye underwent simulated insertion in an attempt to provide some degree of control for a placebo effect. The aetiologies of dry eye for these subjects included Sjögren's syndrome, drug induced dry eye and filamentary keratitis. In all cases it was intended to occlude both the superior and inferior puncta of the right eye, but in some cases only the inferior punctum was occluded because of the greater difficulty in inserting a plug in the superior punctum. Subjective improvement in symptoms was significantly more marked after occluding the two puncta on the treated side (77%) than the other side (placebo) (17%). A significant improvement in Rose Bengal staining and for Schirmer test results was also shown.

Castillo et al (1994) carried out a quantitative comparison of conjunctival and eye lid micro-organisms in dry eye patients before and after punctal occlusion and compared the results with the findings in normal aged-matched patients. The number of colony- forming units was significantly increased prior to punctal occlusion when compared to post-occlusion and to the normal controls.

It is important to note that occluding one punctum will not reduce tear drainage by 50%. This is because the pump action produced by the blink will cause additional drainage to occur via the other canaliculus. Indeed, Royer et al (1983) reported that cicatrical stenosis caused by trauma in otherwise normal eyes does not necessarily cause epiphora because of an increased drainage via the homolateral canaliculus. Dohlman (1978), referring to cauterisation, suggests that it is important to occlude the homolateral punctum to obtain satisfactory treatment of dry eye syndromes. Fayet et al (1990) reported that the results following occlusion of both puncta on the same side were better than those following occlusion of one punctum only. They conclude that, having decided to carry out the procedure, immediate double unilateral occlusion should be carried out. They suggest that occlusion of one punctum on one or both sides should be reserved for cases when insertion in the upper punctum is difficult. For discussions relating to tear drainage mechanisms the reader is referred to Jones (1957), Maurice (1973), and Doane (1981).

Side effects

Although the risk of infection is minimal once the plugs have been properly inserted, patients should be made aware of such risks before they agree to the procedure. Following insertion the patient must be advised to consult the practitioner if any discomfort, pain, erythema or swelling occurs. Transient minor discomfort is normal for a few hours following any of the procedures.

The one off instillation of a topical antibiotic for prophylactic purposes will offer little or no benefit to the patient, and a full course of antibiosis should not be necessary for most patients. However, Fayet et al (1990) prescribed a combination of neomycin and dexamethasone every six hours for four days for patients in their study.

Maguire & Bartley (1989) reported complications with a smaller sized Freeman plug. In three patients a plug migrated into the canaliculus. In two of these cases the plug was surgically removed. One of these patients had the plug removed from the second punctum because of epiphora and subsequently suffered a stenosis (obstruction) of that punctum. Since this report there have been further design improvements to the Freeman plug but, nevertheless, care should be taken in ensuring the optimum size plug is inserted.

Punctum and intra-canalicular plugs

Clinical indications for punctum and canalicular occlusion with plugs

Plugs may be considered for patients with chronic dry eye (particularly aqueous deficiency), in the absence of infection or other pathology, in which the patient's symptoms are not adequately controlled with tear supplements. This may include contact lens wearers. Patients must be made aware that even if the plugs prove beneficial they may not completely replace other treatment such as the regular use of tear supplements.

Other uses

  1. To enhance efficiency of topical ocular therapeutics (e.g. glaucoma therapy)

  2. To prevent drainage of drugs into the nasolacrimal system in susceptible patients (e.g. the use of topical beta blockers for patients with cardiovascular disease).


Contraindications include:

  1. Allergy to bovine collagen (temporary plugs)

  2. Allergy to silicone

  3. Infective conjunctivitis

  4. Dacryocystitis

  5. Inflammation of the eyelid

  6. Epiphora

Types of plug

There are two broad categories of plug:-

  1. Collagen plugs

    These are "temporary" and dissolve over 4 to 7 days. As such they are useful for diagnostic and prognostic purposes, and are used to predict the likely efficacy of non-dissolvable plugs.

    Plugs are available in a range of diameters (0.2mm, 0.3mm, 0.4mm, 0.5mm, and 0.6mm) and lengths (a "standard" 2mm and a shorter 1.6 mm). They are packaged in quantities of six. At least one manufacturer states that the two "spares" may be utilised as additional inserts in the inferior puncta so that the inferior canaliculi receive two plugs each.

    Procedure for collagen implantation

    Before contemplating punctum or intra-canalicular occlusion a full eye examination and tear assessment (for example, biomicroscopy, fluorescein and Rose Bengal staining, and Schirmer test) should be carried out. The results of these tests are important for follow-up comparisons. Other tests and clinical indicators (e.g. lysozyme levels, lactoferrin test, impression cytology, phenol red thread test, Tearscope) are in clinical use and may aid the differential diagnosis of tear component deficits.

    The practitioner should be satisfied that the patient has not obtained satisfactory symptom relief by using artificial tears, ocular lubricants or other interventions.

    Once the practitioner has decided that punctum plugs are a clinical option the procedure should be explained to the patient. If both eyes are "dry" it useful to carry out the procedure on one eye initially, to allow both the patient and practitioner to compare its effect.

    White et al (1989) examined lacrimal drainage using a scintigraphic technique and found no significant difference between the superior and inferior canaliculi. As it tends to be easier to insert a plug into the inferior punctum than the superior, if only one punctum is to be occluded it is preferable to choose the inferior.

    Check the integrity of the corneal and conjunctival epithelium using diagnostic stains prior to inserting the plug(s).

    Examine the punctum with the biomicroscope. The punctum may be viewed by partly everting the lid towards the examiner. With a little experience the practitioner will be able assess the size of the punctum. Note its shape and size.

    Anaesthetise the region. This is most easily carried out by instilling one drop of Benoxinate Hydrochloride 0.4% or other topical anaesthetic into the conjunctival sac and waiting for the drug to drain via the puncta. Alternatively, a cotton-wool tipped applicator soaked in anaesthetic may be held for 30 seconds against the punctum. If the punctum appears small it may be dilated by gently inserting and rotating a fine stainless steel dilator (obtainable from the plug manufacturers) placed just into the punctum. Alternatively choose a small diameter plug.

    Generally 0.3mm is a useful diameter to use as a starting point. The procedure may be safely carried out by pulling the lid away from the globe and instructing the patient to look to the temporal side. This will reduce the risk of accidental trauma to the cornea.

    Grasp the collagen implant with fine forceps towards one of its ends, and after inspecting it under the microscope for any irregularities, insert the other end into the punctum. Manipulating the lid with the other hand will help positioning of the punctum..

    Release the plug from the grip of the forceps, the tip of which may then be used to gently push the plug down until it disappears completely. Alternatively, the punctum dilator may be used as a utensil to push the plug beyond the punctum opening.

    Figure 2 illustrates the collagen plugs positioned in the canaliculus. After insertion, the force of the blink and direction of the tear flow may cause the implant to migrate further into the horizontal canaliculus. Once wet, the plug will swell to twice its original diameter.

    Repeat the process for the other punctum as required.

    The patient should be reviewed after one to two weeks. If the patient reports resolution of symptoms and/or there is clinical evidence of resolution of signs, then the use of "permanent" silicone plugs may be considered.

    The author has noted that some patients report a continued resolution of symptoms weeks after insertion of collagen plugs. There are a number of possible reasons for this.
    Firstly, a possible placebo effect.
    Secondly, the extra volume of tears during the period of occlusion may enable resolution of chronic disturbances of epithelial cells or the epithelial basement membrane. If this latter hypothesis is correct then it may be useful to assess the patient a few weeks after occlusion with collagen plugs before considering silicone punctum or intra-canalicular plugs.
    A third possibility is that the collagen plug precipitates a stenosis of the canaliculus.

  2. Silicone plugs

    These are "permanent" in that they do not dissolve. However they can be removed if necessary. There are two main categories of silicone plug for dry eye:

    a) Punctum plugs (e.g. Eagle vision Freeman plug, FCI® Umbrella plug, and Oasis® Soft Plug).

    Figure 3 illustrates a Freeman plug.

    b) Intracanalicular plug

    Figure 4 illustrates a Herrick Lacrimal Plug

    Insertion of silicone punctum plugs

    Following topical anaesthesia, the optimum size of plug should be determined by a punctal gauging system such as that produced by Eagle Vision.

    This consists of two instruments each having a gauge tip on each end. One instrument has a 0.5mm diameter gauge tip on one end and a 0.6mm diameter tip on the opposite end. The other instrument offers 0.7mm and 0.8mm gauge tips.

    Figure 5 Figure 6 Figure 7

    Too small a gauge size will encounter little or no resistance upon entering the punctal opening (Figure 5), whereas too large a gauge size will offer too much resistance both entering and exiting the punctal opening. (Figure 6). The proper gauge size will moderately flex the punctal ring when both entering and exiting the punctal opening. (Figure 7).

    The latest version of punctum plugs (e.g. the Freeman "tapered shaft " plugs) are available "pre-loaded" on applicator tools in four sizes (0.5mm, 0.6mm, 0.7mm and 0.8mm). The various designs and sizes of the Freeman punctum plug are positioned on the end of the applicator tools. The punctum should then be dilated.

    Figure 9
    The applicator with the pre-loaded plug is inserted into the punctum until the dome head is seated on the surface of the punctum, the release button pressed and the applicator withdrawn.

    Figures 10 and 11

    The procedure is repeated for the other puncta as required.

    Disadvantages of silicone punctum plugs

    1) These plugs may be extruded. Willis et al (1987) reported that 22% of their patients (four out of eighteen) showed extrusion of punctal plugs within two weeks of placement. However, they commented that three of these patients did not require dilation of the puncta before insertion. This suggests that the plugs were of too small a size. Subsequent improvements to the design of plugs since these reports may well give greater stability.

    2) Some patients report minor lid discomfort. However, the latest versions of the Freeman and the "angulated" design produced by FCI® may offer enhanced comfort.

    Advantage of silicone punctum plugs

    1) The presence or otherwise of a punctum plug in the punctum is apparent.

    2) In the event of unwanted side effects they can be removed easily with forceps.

    Insertion of silicone intra-canalicular plugs (Lacrimedics Inc).

    The punctum should be inspected and an estimation made as to the optimum plug size. Patients with large puncta should receive the 0.5mm plug and patients with smaller puncta should be fitted with the 0.3mm plug

    The punctum should be anaesthetised.

    Following removal of the insertion stilettes from the sterile packaging the practitioner separates one stilette. The length of the stilette should be shortened to a manageable and stable working length by pulling it through its Styrofoam holder.

    The lid is everted to bring the punctum into view. The stilette is then positioned vertically above the punctum and the plug is inserted until the collapsible bell is resting on the punctum.

    Figure 13

    The stilette is then rotated so that the plug is pointing nasally along the canaliculus. This straightens the angle between the vertical and horizontal canaliculi.

    Figure 14

    The stilette is gently advanced so that the collapsible bell eases through the punctal opening.

    The plug should be advanced a further 2mm to 3mm nasally. The bell will reopen inside the canaliculus.

    Figure 15

    The stilette is then withdrawn leaving the plug in place. The force of the blink and direction of the tear flow will cause the plug to migrate 6mm to 8mm into the horizontal canaliculus where it lodges as the canaliculus narrows.

    Figure 16

    Repeat for the other punctum if required

    Advantage of the intracanalicular plug

    1) Once inserted it may be less irritating to the patient's lid than the Freeman type plug.

    Disadvantages of the intracanalicular plug

    1) It is difficult to confirm whether the plug has been extruded via the common canaliculus. Silicone is radiopaque and a plug may be located with an X-ray.

    2) Lacrimal irrigation or probing may need to be employed if it becomes necessary to remove the plug.


The practitioner should ensure that the patient understands the need for ongoing follow-up examinations and seeks immediate attention in the event of the onset of any untoward symptoms.


The availability of punctum and intra-canalicular plugs provides the practitioner with various diagnostic, prognostic, therapeutic and prophylactic techniques to offer patients suffering from certain types of chronic tear deficiencies which have been inadequately controlled with other interventions.

Collagen plugs provide an invaluable prognostic indicator of the likely efficacy of more permanent occlusion using surgery, punctum or intracanalicular plugs.

Occlusion of one punctum will not reduce tear drainage by half. Indeed the other canaliculus may take over the entire drainage (Fayet et al, 1990).

However, the present author suggests a step by step conservative approach as follows:

  1. Occlude the inferior punctum with a collagen plug for prognostic purposes. It is generally easier to insert any type of plug into the inferior punctum compared to the superior.

  2. If an improvement in signs/symptoms is noted then occlude one punctum using a non-dissolvable plug.

  3. If the longer term improvement is not adequate then occlude the homolateral punctum with a temporary collagen plug.

  4. If epiphora does not occur and there is a further improvement in signs/symptoms then occlude the homolateral punctum with a non- dissolvable plug.

The patient may need to continue using artificial tears following occlusion.

The primary eye care practitioner- the optometrist - has an important role to play in the management of patients with dry eye, and as such may find the use of punctum and intra-canalicular plugs of benefit to some patients.


Beetham W.P., (1935) Filamentary keratitis. Trans Am Ophthalmol Soc, 33, 413-435

British College of Optometrists (1995) Council Meeting 10th May, minute C25

Castillo, N. M., Kosrirukvongs, P., Gritz, D.C., Goosey, J.D., Folkens, A.T., and

Yee, R.W. (1994) Quantitative ocular microbial flora of dry eye patients pre and post punctal occlusion. Invest Ophthalmol Vis Sci, 35, 4, 1691

Catania, L.J. (1995) Primary Care of the Anterior Segment. 2nd Ed. Appleton & Lange, Norwalk, Connecticut

Doane, M.G. (1981) Blinking and the mechanics of the lacrimal drainage system. Ophthalmology, 88, 844-851

Dohlman, C.H. (1978) Punctal occlusion in keratoconjunctivitis sicca. Ophthalmology, 85, 1277-81

Fayet, B., Bernard, J.A., Ammar, J., Karpouzas, Taylor, Y, Abenhaim, A., Renard, G., Pouliquen, Y. (1990) Treatment of chronic dry eye with temporary punctal plugs. J. Fr. Ophthalmol. 13, 3, 123-133

Foulds, W.S. (1961) Intra-canalicular gelatin implants in the treatment of kerato- conjunctivitis sicca. Br. J. Ophthalmol. 45, 625-627

Freeman, J.M. (1975) The punctum plug: evaluation of a new treatment for the dry eye. Tans. Am. Acad. Ophthalmolol. Otolaryngol., 79, 874-879

Gilbard, J.P. (1985) Tear film osmolarity and keratoconjunctivitis sicca. CLAO J., 11, 243-250

Gilbard, J.P. (1989) Effect of punctal occlusion by Freeman silicone plug insertion on tear osmolarity in dry eye disorders. CLAO J., 15, 216-218

Jones, L.T. (1957) Epiphora II. Its relation to the anatomic structures and surgery of the medial canthal region. Am. J. Ophthalmol., 43, 203-212

Maurice, O.M. (1973) The dynamics and drainage of tears. Int. Ophthal. Clin., 31, 103-116

Maguire, L. L., and Bartley, G.B., (1989) Complications with the new smaller size Freeman punctal plug, Arch. Ophthalmol., 107, 961-962

Turberville A.W, Frederick W.R., Wood T.O. (1982) Punctal occlusion in tear deficiency syndromes. Ophthalmology, 89, 1170-2

Willis, R.M., Folberg, R., Krachmer, J.H., Holland, E.J. (1987) The treatment of aqueous deficient dry eye with removable punctum plugs. A clinical and impression-cytologic study. Ophthalmology, 94, 5, 514-518

Further reading

British College of Optometrists (1996) Use of Punctum Plugs - Guidelines (in preparation)

+44 1382 774777
Useful addresses
ManufacturerUK representativeProduct
Alcon LaboratoriesAlcon LaboratoriesTears Naturelle Punctal Plugs
6201, South Freeway,
Fort Worth,
Texas 76134-2099
Tel +1 800 679 6717

Eagle VisionOptimed LtdFreeman punctum
6263 Poplar Avenue,+44 1386 561845
Suite 650, Memphis,
Tennessee 38119, USA
Tel. +1 901 682 9400
Fax. +1 901 761 5736

FCI, 20 Blvd GallieniNovamed Ltd,Umbrella punctum
BP 111
92134 Issy-Les-Moulineaux
Cedex, France
Tel. +33 1 40 93 07 77
Fax. +33 1 40 93 05 62

Lacrimedics IncAltomed LtdHerrick intracanicular
190 North Arrowhead Ave+44 191 519 0111
Rialto, CA 92376 USA
Tel. +1 800 367 8327
Fax +1 714 873 3823

Oasis,Soft Plug
514 S. Vermont Ave
Glendora, CA 91741,
Tel. +1 800 528 9786
Fax +1 818 914 2285

Odyssey Medical Inc,Parasol Punctal Occluder
1710, Shelby Oaks Drive, Suite 21,
Memphis, TN 38134
Tel +1 888 905 7770
Fax +1 901 382 2712
Note: all the above manufacturers produce collagen plugs.


The author wishes to acknowledge the assistance of Michael J. Watermeier of Eagle Vision and Susan M. Thomas of Lacrimedics Inc. for their assistance in preparing this paper.

The author has no commercial interest in any of the products described in this paper.