Over the last decade our understanding of dry eye has improved immensely, as have the management options available to the dry eye practitioner. For example, the greater understanding of the role of lipid deficiency and meibomian gland dysfunction (MGD) and the ready availability of home and in-practice lid hygiene products to help improve the condition, has undoubtedly improved many patients’ outcomes. Interestingly during this time, the use of punctum plugs, popular with both optometry and ophthalmology in the US, has remained a niche market in the hands of an ‘expert’ few.
This under-utilised dry eye management technique is most likely to be carried out by ophthalmologists in the UK, despite being a simple and relatively safe procedure that is well within the scope of high street optometric practice. As a consequence, a large group of patients, including CL wearers, are not being optimally managed and are continuing to suffer dry eye symptoms unnecessarily.
Recent UK market research 1 has revealed that ECPs perceive punctal occlusion as something of a last resort. Interestingly this is not the view of the latest DEWS report, which advocates considering punctum plugs at dry eye severity level 2, on its four-point scale 2 (Table 1). For their treatment algorithm, DEWS researchers considered only those therapies with solid evidence in the literature to support efficacy. It is worth noting that DEWS actually places secretagogues and moisture goggles in level 2, but that seems early to take these measures.
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Overview
Punctal occlusion is a procedure that helps retain tears on the ocular surface regardless of the causative factor of the tear films depletion.
It is designed to provide a simple, short or long-term and reversible means of reducing or eliminating tear drainage via the punctum. Plugs are easy to insert (and remove where applicable) and generally comfortable for the patient after placement.
Anecdotally, practitioners of the ‘art’ report favourable results following use of the technique. Punctal occlusion has previously been reported to be very effective for the treatment of dry eye, relieving symptoms, improving TBUT, reduced corneal staining, increased lower tear meniscus height, improved visual acuity, improved conjunctival goblet cell density and enables patients to reduce their use of lubricants.3-9
Who is a candidate?
Broadly speaking, any healthy dry eye patient where there is an absence of chronic, clinically significant inflammation and where other obvious causes for the dry eye (such as meibomian gland disorders) are being appropriately managed can be considered for punctal occlusion.
With 50% of contact lens wearers dropping out as a result of discomfort, often related to dry eye, punctal occlusion is also a legitimate management option for contact lens associated dry eye (CLADE). Inserting a contact lens uniquely challenges the tear film and ocular surface, even in the healthy eyes of patients who otherwise have no real dry eye symptoms.
Age-related correlations have been shown for tear evaporation, volume, flow and osmolarity,10 which might explain why previously happy CL patients start to report dryness symptoms after many previously successful years of wear. Currently, these patients are often managed by the use of ocular lubricants and/or changing the lens material.
Advocates report the use of punctal occlusion as an effective management strategy for CLADE.11-12 This is likely to be due to dealing more effectively with the underlying cause of the wearer’s problem, especially when related to reduced tear volume.
Suitability
One of the regular questions clinicians ask regarding punctal occlusion is: ‘will I do more harm than good?’, particularly relating to concerns regarding tear film stagnation. There is no doubt that in the presence of chronic inflammation, any potential build-up of inflammatory tissues is undesirable and will only exacerbate symptoms. As such the ability to diagnose clinically significant inflammation will eliminate this risk and improve the number of successful patient outcomes from plugging.
Detecting inflammation
Until recently there was no definitive test for inflammation and consequently nothing to reassure the clinician that punctal occlusion was a legitimate option for an individual patient.
InflammaDry is a point of care diagnostic test (POCT) that enhances our understanding of the patient’s dry eye with a simple pass or fail result.13 It is the first and only POCT that detects Matrix metalloproteinase-9 (MMP-9), a biomarker for inflammation that is consistently elevated in the tears of patients with dry-eye disease.14
MMP-9 is a non-specific marker for inflammation and in conjunction with patient history and assessment of clinical signs, will help confirm a diagnosis of dry eye.InflammaDry is reliable with sensitivity levels of 85% and 94% specificity.15 It is a relatively low cost disposable test that is simple to use and gives a definitive positive or negative result in just 10 minutes.
MMP-9 activity is significantly higher in patients with dry eye and increases as dry eye severity progresses16 (Table 2). In a normal tear film the level of MMP-9 is low at between 3 and 40ng/ml. Abnormal levels of MMP-9 (=40ng/ml) have been shown to correspond with moderate-to-severe dry eye disease,16 as defined by the Dry Eye Workshop (DEWS) Report.17
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Having administered the test (Figure 1A) there will be a blue line in the result window to indicate that the test was carried out correctly and enough tear sample taken to be valid. If there is no other line present, then the test result is negative.
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Should a pink/red line be visible alongside the blue line then the test is positive with MMP-9 levels (=40ng/ml (Figure 1B).
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There are three outcomes for a patient complaining of dry eye symptoms: a positive result; a negative result with an absence of any clinical signs; or a negative result with other clinical signs. When considering whether or not to plug a patient the latter negative result means plugging is safe to consider.
Punctal plugs
All plugs can be broadly split into two types: Those for temporary use and those for more permanent placement. Examples of some of the permanent plugs available in UK can be seen in Table 3.
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The advantages of punctal occlusion can be said to be:
- No dependence on patient adherence, skill or dexterity
- Reduced patient dependence on artificial tears
- Reversible with a good safety profile
- Keeping patient management and spend in the practice
Permanent Plugs
Permanent plugs (so named as they do not dissolve and can be easily removed at any time) are made of medical grade silicone material. They have a dome (or cap) at the top of their shafts that prevent them disappearing down the punctum. The typical anatomy of this type of plug can be seen in Figure 2.
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They are typically sold in three formats – sterile pre-loaded, sterile bulk and non-sterile bulk. The latter two formats are designed for the practitioner to load into a reusable inserter. The sterile pre-loaded format is the easiest and safest to use, especially for the novice and/or low volume fitter.
Absorbable Synthetic Implants
Absorbable plugs are made from an absorbable copolymer of glycolic acid and trimethylene carbonate (Figure 3), fundamentally the same synthetic material as modern surgical sutures. Consequently, their key feature is that they ‘dissolve’ after three months. This makes them an ideal low cost way of trialling the potential success of occlusion.
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Whilst developed primarily for one off use (eg post-surgery such as LASIK) another benefit of their three-month ‘life’ in optometric practice is that they can be used on a planned replacement programme. This also has the benefit of spreading the cost for all dry eye patients, including contact lens wearers suffering associated dryness, as they can add the cost to their existing direct debit payment plan.
Fitting punctum plugs
As with any procedure, punctal occlusion has benefits and risks. Most types of plug available today have a very high safety profile, with epiphora, conjunctival irritation and extrusion being the only known complications. Prior to use, practitioners must always review the benefits and risks with their patient.
As with any aspect of clinical practice and before embarking on fitting plugs to patients, it is important to have completed appropriate learning and hands-on training. Additionally, practitioners must ensure they have adequate professional indemnity insurance. Cover for punctal occlusion is provided in the AOP and ABDO policies for optometrists and contact lens opticians respectively. Finally, before embarking on fitting a patient, the use of an appropriate informed consent form should be considered.
Sizing
Traditionally silicone plug designs are manufactured in sizes ranging from 0.2mm to 0.9mm in 0.1mm steps and so accurate measurement of the size of the punctum opening is necessary in order to select the correct plug to be fitted. Sizing tools are available from the manufacturers in order to assist the fitter in selecting the correct size plug. Historically, with plug retention rates in several studies being reported at between 49.3% and 69.5%,7,9,18,19 selecting the correct size plug, especially one that’s not too small, is essential.
More recent advances in plug technology has resulted a self-dilating design with the benefit of a simpler sizing approach of small, medium or large. This type of design has also improved the retention rate with one study of 216 eyes reporting 92% retention after 1-year.20
Dilation
The punctum can be dilated using a special tool (Figure 4) or a dilator tip on the end of some manufacturers inserter. The dilator is gently inserted into the punctum to widen it very slightly before promptly inserting the plug. Generally, this step is not required when using a non-dilating plug design.
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Insertion
Permanent plug: Silicone plugs come with an insertion instrument to simplify the process (Figure 5a).
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Positioning the plug end of the insertion instrument over the patient’s punctum (Figure 5b), the plug is gently inserted into the punctum until the dome is flush with the lid margin. Once you have determined the plug is in its proper position, either depress the release button on the inserter (or squeeze the inserter depending upon the design). After insertion, carefully inspect the punctal area to confirm the plug has been properly placed for optimum occlusion.
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Absorbable implants: These do not have a specific insertion instrument and are usually supplied in pairs held in a foam holder and in a sterile pouch. After opening the pouch, the implant is removed from the foam holder using jeweler’s forceps. A small amount of lubricant may be used on the implant or punctum in order to facilitate insertion into the punctum. Grasping it with jeweler’s forceps (Figure 6), the implant is inserted partially through the punctal opening. Once in place, the implant is released and the tip of the forceps used to push the implant the rest of the way through the punctal opening and into the canaliculus. Following insertion, the punctum should be inspected to ensure the implant is below the punctal opening.
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Removal
If removal of a permanent plug is indicated, it can be gently grasped with forceps by the vertical shaft immediately underneath the exposed dome. Then, by gently pulling upward using a rocking motion, the plug can be fully released from the punctum.
To anaesthetise or not to anaesthetise?
The necessity of anaesthesia in plugging is a matter of some conjecture. On the one hand, having an anaesthetic instilled will generally relax the patient, as well as reducing the sensation of the plug being inserted. On the other hand, depending on the anaesthetic used, there is a level of irritation caused by the anaesthetic itself and some patients will find this worse than the feeling of the plug being inserted. Different plug designs, practitioner skill and experience, as well as individual patient pain thresholds will also create differing levels of discomfort for the patient that may be relieved by anaesthesia.
For newer non-dilating designs, the insertion and removal of the plug is relatively comfortable, further challenging the use of anaesthetics.
Discussion
Despite practitioners reporting that plugs are easy to insert and remove, the perception of non-fitters is that the procedure is difficult and requires a great deal of training. Concerns about the invasive nature of the procedure have also been raised. However, it is the author’s personal experience that a skilled contact lens practitioner will quickly and easily pick-up the technique.
Another perceived concern seems to be the invasive nature of the technique, possibly due worries the plug could easily become embedded in the canaliculus. Whilst anecdotes of this rare outcome exist, there is no data available to support its actual incidence. To provide perspective there is a wealth of data on contact lens complication rates and in particular the risk of microbial keratitis and subsequent loss of vision. Small risks do not stop most practitioners regularly fitting new patients in what is a fundamentally safe modality. Ultimately, it is for the individual practitioner to consider the risk/benefit scenario, ideally in consultation with the patient.
Though dry eye symptoms can be significantly reduced with the use of artificial tears of varying formulations and viscosity, patients can feel burdened with the frequent use of such aqueous tear enhancers. This, and the difficulty some patients have instilling drops, can cause them to become non-compliant with the resultant resurgence in symptoms. For such patients punctal occlusion is a legitimate management strategy worthy of practitioner and patient consideration.
Conclusion
Punctal occlusion is a simple dry eye management technique that can help resolve dryness symptoms in contact lens and non-contact lens wearers alike. In the past there was a risk that some patient’s symptoms may be exacerbated by plugging due to the risk of accumulation of inflamed tissues on the ocular surface. This risk is now largely removed by introducing a testing protocol that includes InflammaDry.
Most dry eye patients are currently being denied access to the relief of their symptoms that can be provided by some form of punctal occlusion. As such improved access to this treatment can only be beneficial in helping more patients break the misery that their dry eye causes them. With appropriate training the technique is safe and simple to perform by optometrists and contact lens opticians, making high street optometry ideally placed to deliver this service and improve the quality of life of many dry eye sufferers.
Finally, punctal occlusion keeps the practitioner in control and right at the heart of the patient’s care. As a result, the patient will more likely be retained by the practice, potentially improving compliance with other advice given with regards to their dry eye care.
This is rarely the case when simply recommending the ad-hoc use of over-the-counter products, as pharmacies and supermarkets will testify; a situation that is neither in the long-term interest of the patient’s, nor the practice’s, well-being.
Nick Atkins is a contact lens specialist and joint managing director of Positive Impact
References
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