Continuing Education

Author: Michelle Hanratty

View PDF

Michelle Hanratty gives an overview of the detection and treatment options available for dry eye, and describes how to fit punctum plugs (C4635, one standard CET point)

This module is now closed - you cannot earn any CET points.

THIS ARTICLE IS BEST VIEWED ON A PDF FORMAT

Dry eye is a condition that is frequently encountered in both optometric practice and hospital clinics, with patients describing a range of symptoms from mild discomfort to severe burning sensations.

As a multifactorial problem, there is not always an easy solution and plugging the punctum is just one of several management options.

A patient with dry eye can be more successfully managed if the practitioner has an understanding of the contributing factors and a systematic approach to treatment.

We know that dry eye is the commonest cause of eye irritation in people over 65 years of age and that it is 53 per cent more common in women than in men.1

Longitudinal studies in dry eye are not common and the Beaver Dam Eye Study was probably the most significant project in recent years. It began in 1988 with follow up investigation until 2000 and it found that an average of 14.4 per cent of the 3,722 participants had dry eye as determined by patient history. Increasing age was also shown to be a significant factor, with the prevalence of dry eye rising from 8.4 per cent in the subjects under 60 years of age to 19 per cent in those of over 80 years.

Other studies have also been conducted where the prevalence of dry eye was measured according to actual patient symptoms. The results show a much higher incidence, ranging from 33 per cent to 57 per cent.2,3,4

These studies were carried out in different countries and so it is not certain whether the variation between these studies is due to the ethnicity of the subjects or environmental factors. Other factors known to affect the likelihood of dry eye include eyelid disorders, medication, environmental factors, contact lens wear and corneal surgery.

DETECTION OF DRY EYE

History and symptoms: In some cases medical history may cause or predispose the patient to dry eye (see Table 1). Patients with dry eye often complain of one or more symptoms ranging from stinging, grittiness or foreign body sensation, to soreness and itchiness. In severe cases, the symptoms can include pain, burning, blurred vision or photophobia.

These can be graded using the McMonnies et al questionnaire which scores patient symptoms with 14 questions. A total score of 14.5 or more is consistent with a diagnosis of dry eye, with scores above 14.5 having an 87 per cent sensitivity and specificity for dry eye diagnosis.5

Anterior eye observations: Careful examination of the eyelids, tear film, conjunctiva, and cornea should be carried out to check for clinical signs of tear dysfunction, which lead to dry eye (see Table 2).

Diagnostic procedures: Tear film assessment by means of tear prism height, tear break up time and tear volume tests help to determine the diagnosis of dry eye. Paradoxically, some patients can have a greater tear volume due to an excessive reflex tearing response to corneal surface desiccation. Patients whose results are outside of the normal (see Table 3) may benefit from treatment.

INDICATIONS FOR PUNCTAL OCCLUSION

Prior to punctal occlusion therapy, the practitioner should attempt to alleviate dry eye symptoms by changing any lifestyle or environmental factors that may be contributing to the problem (see Table 4). In particular, problems with lid hygiene or poor contact lens care compliance should be dealt with. Referral to a medical practitioner may also be required to treat any underlying pathology such as recurrent inflammation.

It is worth noting that dry eye symptoms caused by meibomian gland dysfunction will not be resolved by punctal occlusion, in fact they may be exacerbated as inflammatory mediators remain in contact with the ocular surface for longer, resulting in further inflammation.

Tear supplements are the next line of attack and there is a wide range to choose from depending upon the degree of viscosity required and whether or not a mucolytic or mucomimetic is necessary. It is also worth considering whether the patient needs a tear substitute or a lubricant such as liquid paraffin. A list of common preparations are also summarised in Table 4.

Tear substitutes are the main types of treatment for most dry eye patients, although frequent and regular application is needed for this therapy to be successful. For some patients, frequent application may not be convenient or possible and in others, with moderate to severe dry eye, tear substitutes provide inadequate relief. In such cases, the use of punctum plugs is indicated.

Punctum plugs are an efficient way of increasing tear volume by reducing drainage through the puncta and are beneficial to those patients who suffer from an aqueous deficiency. Punctum plugs may also become a necessity if the patient has dexterity problems due to arthritis or if they are sensitive to preservative agents and do not want the high ongoing costs of single use, preservative-free products. Other indications include use with therapeutic agents to increase the ocular contact time or prophylactic fitting prior to refractive laser eye surgery to minimise disruption to the tear film.

TYPES OF PUNCTUM PLUGS

Temporary plugs

These are used to control dry eye symptoms for a short period of time and are very useful for confirming the diagnosis of dry eye. They also demonstrate the potential efficacy of permanent plugs to the patient. These plugs are cylindrical in shape and are made with either collagen or a synthetic substitute.

As collagen plugs can be manufactured using either bovine or porcine products, a synthetic alternative may be the more practical choice as there will be some patients whose religious or lifestyle beliefs do not allow the use of animal products.

Temporary plugs are placed in the punctum using forceps, and they swell to fit the opening on contact with fluid in the canaliculi. There is a selection of diameters available to optimise fit. Collagen plugs usually last for approximately five days, after which they gradually dissolve away and any symptomatic respite that the patient may have felt is lost. Synthetic plugs tend to last between 10 and 12 weeks in most patients and are also known as extended duration plugs.

Permanent plugs

Traditional plugs tend to be of the Freeman type (see Figure 1a), made of soft silicone and sit in the punctum. There is a small lip at one end of the plug which allows it to sit on the lid margin and the other end is tapered to aid insertion. The plug is visible upon examination and it can be removed with forceps if necessary. The plugs are available in a variety of sizes.

For ease of use, these plugs are available pre-loaded onto a single-use inserter which has a punctum dilator conveniently located at one end (see Figure 1b. Practitioner training is required prior to fitting these plugs as inaccurate estimation of the punctum size may lead to too small a plug being fitted. If this occurs, there is a significant risk of migration into the canaliculus, which may then lead to infection, epiphora or dacryocystitis. A surgical procedure may be required to remove a migrated plug.

Some patients dislike punctum plugs as they are visible upon inspection and spontaneous loss is quite common,6 which necessitates a repeat visit to the practitioner. For these patients, the intracanalicular Herrick plugs may be more appropriate. However, they are more invasive and some skill is required to place them correctly into the canaliculus.

The Form Fit plug

The Form Fit plug is an innovative product which combines the ease of fitting of a collagen plug and the invisibility and security of an intracanalicular plug. The plug is supplied on a pre-loaded inserter that dispenses the plug from within a polyamide sheath (Figure 2a). The plug is made of a hydrogel material which absorbs fluid and swells to completely fill the space in the canaliculi (Figure 2b).

The Form Fit plug is marketed as a 'one size fits all', which eliminates the sizing of the punctum and as the practitioner does not need to order different sizes to keep in stock, it minimises the risk of wastage.

Although the Form Fit is a permanent intracanalicular plug, it can be easily removed. The hydrogel material from which the plug is made does not dissolve away under normal lacrimal conditions, but a forced water pressure via an irrigation cannula will dissolve the plug. It is then expressed via the normal lacrimal drainage system. The ease of insertion and reversibility of this procedure makes the Form Fit appealing to use.

FITTING PROCEDURE

Consent process: The risks and benefits of the procedure should be explained to the patient and written consent for the procedure obtained. Serious complications with punctal occlusion are extremely rare, but like any medical procedure, it does have some risks which include: no improvement in dry eye symptoms the plug becoming dislodged and falling out the plug migrating into the tear drainage canal and infection or inflammation.7

The risks are much less with dissolvable plugs. The patient should also be told to expect some minor irritation in the punctal area for one or two days following the procedure. Temporary plugs should be fitted to all patients to ensure that adequate symptomatic relief is achieved and without epiphora.

Procedure - temporary plugs

◆Instil topical anaesthetic into both eyes, with one drop being allowed to fall onto the punctum

◆Examine the punctum. Experience will enable the practitioner to grade the punctum into categories of small, medium and large. Until then it is best to start with a medium-sized plug (usually around 0.4mm)

◆Remove the outer packaging to expose the plugs which are placed in a foam holder and place within reach of the slit lamp

◆Position patient and slit lamp so that the punctum to be occluded is in focus when pulled temporally downwards. Keeping the patient and the slit lamp still, lift the plug out of the holder and bring forceps close to the patient's lower lid

◆Then, looking through the slit lamp eyepieces pull the lower lid in a temporal and downwards motion to expose the punctum and elongate the canaliculi. Place the plug into the punctum (Figure 3a). The plug should slide in with only slight resistance, if there is too much resistance a smaller plug is required. If there is no resistance a larger plug will be required

◆Using the forceps, quickly push the plug down into the punctum (Figure 3b). When the plug is in position, it should not be visible at all ( Figure 3c)

◆Release the lower lid and then repeat for the other eye.

A follow-up appointment should be arranged for a few days after the plugs are expected to dissolve away. The patient should report a lessening of dry eye symptoms and a reduced need for tear supplements. Permanent plugs can then be fitted.

For the practitioner who is relatively new to fitting punctum plugs, it makes sense to start with the Form Fit, which is easy to fit and with minimal potential side effects. The procedure for the Freeman-type plug is also included for completeness.

Procedure - Form Fit plugs

◆After instillation of anaesthetic (see previous method), use a dilator to flex the punctal ring in preparation for inserting the plug (Figure 4a)

◆After positioning the patient and slit lamp accordingly, hold the plug applicator between forefinger and thumb. Then with the other hand, pull the lower lid firmly in a temporal and downwards direction

◆Push the plug applicator into the punctum until the polyamide sheath is no longer visible (Figures 4b and 4c), then squeeze the applicator between thumb and forefinger to dispense the plug

◆Release lower lid and repeat for the other eye.

Procedure - Freeman plugs

◆After instillation of anaesthetic, use a punctal gauge (Figure 5a) to estimate the size of the punctum. Starting with the smallest, place each sizing gauge into the punctum in turn until there is only a slight degree of resistance to removal. This indicates the correct size of plug to use

◆Position patient and slit lamp as above method and then push the plug into the punctum (Figure 5b) until the lip of the plug is flush with the surface of the punctum. Squeeze the applicator between thumb and forefinger to release plug

◆Release lower lid and repeat for the other eye.

AVOIDING PROBLEMS

Approximately 60 per cent of the tear volume is drained via the lower puncta,8 so patients who have been fitted with punctum plugs should be reminded that their symptoms may not be completely eradicated and that artificial tear supplements should still be used.

Patients should also be followed up until ongoing signs and symptoms are stable. If patients report an initial improvement and then worsening of symptoms, it is worth ensuring that the plug is still in place (in the case of a silicone plug). Occasionally, it may be necessary to plug the upper puncta.

If a patient reports any discomfort in the punctal area, slit-lamp examination should be performed. Occasionally, the silicone plug can become dislodged and cause a foreign body sensation, and so repositioning or replacement of the plug is required.

If there appears to be some redness or tenderness around the canaliculi area, it may be necessary to remove the plug completely and refer to the GP for antimicrobial treatment. Silicone plugs can be removed using fine tipped forceps. Form Fit plugs are removed by performing a lacrimal sac washout using a cannula and sterile water/saline.

CONCLUSION

With an ageing population, dry eye problems will be seen in optometric practice with increasing frequency. Such patients are traditionally referred onto the NHS, with dry eye problems taking up a significant proportion of time in an ophthalmologist's outpatient clinic.9

Optometric management of the uncomplicated cases of dry eye could lead to more appointments being available for other pathology. In addition, uncomplicated dry eye patients will receive the appropriate treatment much sooner in optometric practice than when referred for a routine ophthalmologist investigation within the NHS. Although there will be some cost involved for the patient, the benefits of rapid treatment are likely to outweigh the costs, particularly for contact lens patients.

Additional information

The College of Optometrists has specific guidance relating to punctal occlusion, which can be found in the Member's Handbook.10 Workshops covering the practical training in punctal occlusion and lacrimal sac washout are often available from CET providers. Punctum plug suppliers may also be able to provide or facilitate arrangements for training locally where optometrists are keen to use their products.

References

1 Moss SE, Klein R, Klein BE. Incidence of dry eye in an older population. Arch Ophthalmol, 2004 Mar 122(3): 369-73.

2 Chia EM, Mitchell P, Rochtchina E, Lee AJ, Maroun R, Wang JJ. Prevalence and associations of dry eye syndrome in an older population: the Blue Mountains Eye Study. Clin Experiment Ophthalmol, 2003 Jun 31(3): 229-32.

3 Hom M, De Land P. Prevalence and severity of symptomatic dry eyes in Hispanics. Optom Vis Sci, 2005 Mar 82(3): 206-8.

4 Lin PY, Tsai SY, Cheng CY, Liu JH, Chou P, Hsu WM. Prevalence of dry eye among an elderly Chinese population in Taiwan: the Shihpai Eye Study. Ophthalmology, 2003 Jun 110(6): 1096-101.

5 McMonnies C, Ho A, Wakefield D. Optimum dry eye classification using questionnaire responses. Adv Exp Med Biol, 1998 438: 835-8.

6 Balaram M, Schaumberg DA, Dana MR. Efficacy and tolerability outcomes after punctal occlusion with silicone plugs in dry eye syndrome. Am J Ophthalmol, 2001 Jan 131(1): 30-6.

7 Rumelt S, Remulla H, Rubin PA. Silicone punctal plug migration resulting in dacryocystitis and canaliculitis. Cornea, 1997 May 16(3): 377-9.

8 Murgatroyd H, Craig JP, Sloan B. Determination of relative contribution of the superior and inferior canaliculi to the lacrimal drainage system in health using the drop test. Clin Experiment Ophthalmol, 2004 Aug32(4): 404-10.

9 O'Brien PD, Collum LM. Dry eye: diagnosis and current treatment strategies. Curr Allergy Asthma Rep, 2004 Jul 4(4): 314-9. Review.

10 College of Optometrists Members Hanbook (2005) Use of punctum plugs and intracanalicular occlusion.

◆ Michelle Hanratty is the Refractive Clinic manager at Aston Academy of Life Sciences

Providing exclusive eye care news, information and educational needs every week, including a FREE CET programme. Subscribe to Optician Print Edition.