You would have to have been living on another planet for the last few years, and one where no one uses contact lenses, not to have noticed that discomfort and symptoms of dryness are major problems for many wearers of these vision correction devices. The issue is by no means new, having been reported on for at least the past 25 years.1

Over the intervening period it has become evident that most wearers experience some sort of discomfort problem during their history and for a significant minority, the sensations are so disturbing that giving up contact lens wear completely is an all too common resort. This situation pleases no one, being frustrating for wearers and practitioners, as well as having financial consequences for the contact lens industry as a whole, because growth in the sector is opposed by the drain of regular dropouts.

In recognition of this state of affairs and the fact that effective cures were not obviously available, the Tear Film and Ocular Surface Society proposed that a workshop be convened to draw together the threads of available knowledge in the area of contact lens related discomfort (CLD). The idea was to agree on a definition for the problem and then provide a consensus view on its epidemiology, physiology, causes and treatment, all based squarely on the published evidence.

The whole report involved the efforts of over 80 scientists and clinicians and is structured into 10 sections which can be downloaded individually or collectively from the Investigative Ophthalmology and Visual Science website (www.iovs.org/content/54/11.toc). However, to give Optician readers an overview of the key findings that may be most relevant to their day-to-day clinical environment, this article will focus only on the management and therapy section of the TFOS report.2

Preliminary consultation

The first management imperative for the clinician is to conduct a thorough history, both of the presenting condition and the overall situation of the patient. This is crucial for several reasons, not least of which is that there are a range of conditions, some ocular and others systemic, which might precipitate feelings of discomfort, yet have little to do with the fact that the suffer is wearing contact lenses. Examples might include tear film abnormalities due autoimmune disease, diseases of the eyelid, conjunctiva or cornea (Figure 1) and medicamentosa (irritation caused by drug or preservative use). History taking also provides the opportunity to place the presenting signs and symptoms in the context of personal factors such as the time course of onset, wearing schedule, care system, occupation etc, that may be significant in divining potential causes of discomfort.

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Checking the lens

It may sound obvious but the next thing that should occur is a full assessment of the status of the contact lens both on and off the eye. Physical damage to the lens (Figure 2), deposits and poor fitting can all be evident sources of discomfort, but another factor worth considering is whether the lens is delivering an optimal visual result. Small amounts of blur, whether due to uncorrected astigmatism or inaccurate spherical power have been blamed for interfering with subjective comfort and so it is generally wise to ensure that a full refractive correction is in place.

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Treatment of the symptomatic patient with a clinically acceptable lens

Once satisfied that there are no evident confounding problems, the clinician can concentrate on working out what management strategies may improve the symptomatic condition of the patient. Several potential approaches are identified in the TFOS report and the remainder of this article will deal with each of these in turn. Unless specifically stated otherwise, the comments relate to soft lenses. It is important to appreciate that as the report was evidence based, failure to support a particular method or treatment does not necessarily mean that this would not work; it may simply reflect the lack of formal studies in that direction.

Replacement frequency

More frequent lens replacement would probably be a strategy that many clinicians would think useful and so it is rather surprising that there have been only a handful of studies investigating the benefits of such an approach. Even more remarkable is that historically, the balance of evidence does not strongly favour switching from four to two weeks replacement as a means of improving comfort. More recent work with one type of silicone hydrogel does suggest, however, that daily disposability offers some benefit relative to re-using lenses, irrespective of the care systems involved.

Care systems

It is clear from recently conducted work that for a given lens type, the average comfort response varies according to the care system used. The magnitude of this effect is difficult to predict on an individual basis but appears to be large enough to suggest that switching between care systems, in order to change the preservative or method of disinfection, offers a potentially useful clinical tool in cases where comfort is a problem. Note that the best lens/care system combination need not necessarily come from the same manufacturer. A further important cautionary point here is that factors other than comfort may be affected during the course of making such a change. Thus, a solution giving good comfort responses may perform less well in terms of corneal infiltrates, for example. Keeping the whole clinical picture in mind remains a vital part of management.

Some clinicians have taken the view that it may be the components of care systems in general that are causing the problem and that their patients would benefit if all chemicals were removed from the eye/lens system. The way to achieve this would be to adopt a daily disposable routine, and as mentioned earlier this can be a helpful strategy. Remember, however, that lens packaging solutions contain a variety of additives and if these are deemed undesirable, a pre-insertion saline rinse may be thought necessary as a way to reduce their impact on the eye.

Lens parameters

As mentioned earlier, a good lens fit is an important determinant of comfort and there appear to be some particular aspects of the lens’ design that can be beneficially exploited. For example, a thin, knife edge is preferable to one that is rounded, probably because it sits down more closely to the conjunctival surface thus reducing the interaction with the eyelid.

Lenses that are steeper and larger tend to be generally more comfortable, though care needs to be taken to avoid creating excessive tightness and an immobile lens. Again the mechanism probably involves reducing lens motion and eyelid lid irritation.

This is one area where there is significant knowledge regarding rigid lenses, and while there are some parallels, it should not be surprising, given their characteristic differences, that the advice varies from that for soft lenses. Hence, while larger diameters are again preferable, rounded edges are in this case a good thing, but excessive tightness should be avoided. The value of good fitting technique is again evident here, including the use of posterior toricity in cases of corneal astigmatism (Figure 3). The principle is that respecting the corneal shape, so far as lens back surface alignment is concerned, appears to offer the most benefit.

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Materials

The rationale for switching from one material to another can be multifactorial, but improving oxygen permeability is probably the most common desire. Several studies have looked at the effects of switching from hydrogels to silicone hydrogels. While some of these have found the change to be beneficial, in many cases wearers were simply switched from their old, habitual hydrogels into new, silicone hydrogels; an action that almost guarantees an outcome favourable to the newer lens. Some very recent work, that appeared too late to be included in the TFOS report, gets over this problem by also including a control group who switched from hydrogels to silicone hydrogels.3 Any additional effect of silicone hydrogels can thus be more easily judged and this study did suggest that longer comfortable wearing times may be a possibility for these higher Dk materials. These findings are compelling, but they do of course require confirmation and at present, the question of whether silicone hydrogels offer better comfort th

an conventional hydrogels must remain open.

There is some preliminary evidence showing that lenses whose surfaces offer lower frictional resistance to the eyelid during blinking may give superior comfort,4 but this has yet to be proven to be an effective clinical strategy.

Tear supplemention

The use of eye-drops to improve the wetting of the lens or to supplement the tear film has been the mainstay treatment option for many sufferers of ocular discomfort, whether due to contact lens wear or dry eye in general. Comfortingly, the evidence in the literature is supportive of this and shows that essentially all types of drops, including unpreserved saline, are capable of providing symptomatic relief. More viscous preparations such as those containing carboxymethylcellulose (CMC) or polyvinyl alcohol (PVA) appear to be slightly more effective than saline alone.

As the realities of tear film dynamics mean that all these preparations are eliminated relatively quickly from the conjunctival sac, re-application every few hours will probably be necessary for many users. An additional strategy is to pre-lubricate lenses before insertion and drops containing CMC, methyl cellulose or guar have all been shown to extend comfortable wearing time when used on this basis, at least for some materials. Extending this line of thinking has led to the incorporation of lubricants such as hydroxypropyl methylcellulose (HPMC) into some multipurpose care solutions, with similar results.

Two alternatives that potentially offer a longer lasting solution are hydroxypropyl cellulose (HPC) ophthalmic inserts and punctual plugs. While both these techniques require specialist skills on the part of the clinician, they have been shown to deliver comfort improvements in contact lens wearers that last for several weeks or even months. In the case of punctual plugs, occlusion of both upper and lower puncta with permanent silicone plugs, as opposed to dissolvable versions, appears most effective.

If these methods are deemed too invasive, an allied approach in cases where the contact lens front surface does not wet well, might be to consider the role of blinking. Although the blink mechanism is generally internally regulated so as to avoid ocular surface desiccation, infrequent and/or incomplete blinking both commonly occur, often as a result of activities such as computer use. In cases such as these, exercises to improve the dynamics of the blink are sometimes suggested and guidance documents for how to do this are freely available. Unfortunately, despite several strong advocates for this approach, no one so far has published any evidence supporting its efficacy in reducing symptoms.

Medication

The use of topical medications as a means of controlling CLD has been very poorly studied and the proposed application of any drug in this situation requires extreme caution because the underlying mechanisms are so incompletely understood. Certainly for some compounds, including steroids and anesthetics, there is little justification for their palliative use at all in this setting. While the same argument might well be applied to antimicrobials, there has in fact been one attempt to use azithromycin, a macrolide antibiotic, to treat symptomatic contact lens wearers. Applied twice a day at 1 per cent, the drops were well tolerated and successfully improved the average comfortable wearing time of the study group relative to the control. Obviously this is only one study and the dangers of relying on such single events are highlighted by the experience with another preparation, cyclosporine-A. This IL-2 inhibitor enhances tear production and goblet cell density and has been widely investigated among dry-eyed subjects with favourable results. In contrast, there have been only two trials conducted in the contact lens setting and while the first indicated that comfort improved while using cyclosporine, the second did not. Clearly, understanding the value of this, or any other topical drug, in a contact lens setting requires a much greater weight of data than are available from just one or two trials and so there no topical medications can be recommended at this point in time.

Orthokeratology

Although apparently a fairly radical option, treating intractable cases with orthokeratology (OK) does offer a potential pathway that avoids a complete dropout from contact lenses and the dreaded return to spectacles. OK solves the CLD problem because, as lenses are worn only during sleep, the entire waking period is lens free and therefore symptom free as well. Of course OK comes with its own set of clinical issues and there have been no efforts to establish the success, or otherwise of this refitting strategy in CLD. Nevertheless, it remains an option for suitable cases (Figure 4).

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Summary

CLD is a frustrating clinical problem and the fact that so few definitive treatment options exist in the literature demonstrates the poor state of knowledge surrounding its causes. No single treatment approach will work in all cases and effective management requires careful assessment of each individual to establish the most likely course of action to be taken. Even then, the effectiveness of any single approach may, of itself, be insufficient to deliver complete relief and one or more additional interventions may be required. Despite the best efforts of the clinician, however, our current state of knowledge means that some patients will continue to experience CLD at unacceptable levels until focused research efforts deliver more effective solutions.

Model answers

(The correct answer is shown in bold text)

1 In addressing the issue of discomfort in a contact lens wearer, which of the following is the first management imperative?

A Fluorescein assessment

B Lid eversion

C Checking the fit of a contact lens

D Thorough history

2 Which of the following might be the next action after your answer to question 1?

A Check the status of the contact lens on and off the eye

B Assess the staining pattern if present

C Tear assessment

D Lid eversion

3 Which of the following statements best reflects TFOS findings relating to replacement frequency?

A There is strong evidence that two week replacement is beneficial as compared with four week replacement

B There is strong evidence that four week replacement is beneficial as compared with two week replacement

C There is some evidence suggesting daily disposable wear of one type of silicone hydrogel lens has benefits over re-use of lenses

D Replacement frequency is irrelevant to discomfort

4 Which of the following reflects TFOS findings relating to care systems?

A Care systems have no impact on comfort

B Care systems should be chosen from the same manufacturer of the contact lenses used

C Good comfort should over-ride other considerations such as avoidance of infiltrates

D Switching care systems offers a useful option in attempting to manage discomfort

5 Which of the following is most likely to be related to discomfort?

A A knife-thin edge

B A steep fit

C A rounded RGP edge

D A flat fit

6 Which of the following statements regarding blinking as a means of addressing discomfort is true?

A There is no published evidence supporting its efficacy

B It should always be considered before any other line of management

C It is effective only for RGP lenses

D It should be avoided as no evidence exists for its use as an intervention

References

1 McMonnies CW, Ho A. Marginal dry eye diagnosis: history versus biomicroscopy. In: Holly FJ, editor. The preocular tear film in health, disease and contact lens wear. Lubbock, Tx: Dry Eye Institute; 1986 p32-40.

2 Papas EB, Ciolino JB, Jacobs D, Miller WS, Pult H, Sahin A, et al. The TFOS International Workshop on Contact Lens Discomfort: Report of the management and therapy subcommittee. Investigative Ophthalmology and Visual Science, 2013;54(11):TFOS183-TFOS203.

3 Chalmers RL, Hickson-Curran S, Keay L, Gleason W, Albright R. Struggle with Soft Contact Lens Wear is Addressed by Refitting with Daily Disposable Lenses: 4 Month Follow-up from the TEMPO Registry. ARVO Poster 5458; Seattle 2013.

4 Jones L, Brennan NA, González-Méijome J, Lally J, Maldonado-Codina C, Schmidt TA, et al. The TFOS International Workshop on Contact Lens Discomfort: Report of the contact lens materials, design, and care subcommittee. Investigative Ophthalmology and Visual Science, 2013;54(11):TFOS37-TFOS70.

Associate Professor Papas is the executive director of research and development, and director of postgraduate studies at the Brien Holden Vision Institute and Vision CRC