Managing the contact lenswearing allergy sufferer

Allergy is a widespread problem that currently affects as many as one in three people in Europe at some time in their lives.1 The incidence of allergies is also increasing; the newly formed Global Allergy and Asthma European Network predicts that the problem will reach epidemic proportions by 2015, when half of all Europeans are expected to suffer from some form of allergy.
Allergy sufferers can exhibit a variety of reactions depending on the allergen and the way it is absorbed into the body.2
Seasonal allergic rhinitis, also known as hay fever, is caused by an allergy to the pollen of trees, grasses, weeds or to mould spores. Allergic rhinitis is a general term used to apply to anyone who has symptoms of nasal congestion, sneezing and a runny nose due to allergies. This may be a seasonal condition, as with hay fever, or it may be a year-round or perennial problem caused by indoor allergens such as dust mite.
More than one in 10 people in Europe report that they suffer from hay fever and a further one in eight say they experience other allergies that affect the eyes or cause the eyes to water.3 Recent consumer research in Europe suggests that younger consumers are more likely to claim to be allergy sufferers and report increased use of eye drops; more than half of adult sufferers are in the 18-34 age group and six out of 10 use eye drops.4
Allergy sufferers are also more likely to visit eye care practitioners; three-quarters visit their practitioner more often than every two years.4 It is, therefore, important to be able to identify these patients and be familiar with their ocular signs and symptoms.

Types of ocular allergy
There are six basic allergic eye diseases (Table 1): seasonal and perennial allergic conjunctivitis, in which the allergic response is mediated predominantly by mast cells; vernal, atopic and giant papillary conjunctivitis (GPC), which are associated with a preponderance of T cells; and acute allergic conjunctivitis, which occurs when a large quantity of allergen inoculates the eye and is usually self-limiting.5
Seasonal allergic conjunctivitis (SAC), the most common ocular allergy, is the ocular component of hay fever.5 This condition is responsible for about half of all allergic eye diseases, while perennial allergic conjunctivitis (PAC), the year-round disease, occurs in only about 1 per cent of allergy sufferers.6 Vernal conjunctivitis is a chronic bilateral inflammatory disease that typically affects young males living in warm climates worldwide but has also been reported in Europe and the UK.7
SAC typically occurs when pollen counts are high. The pollen counts given to the media by the National Pollen Research Unit from the end of May to the end of July are for grass pollen, the allergen that affects the majority of hay fever sufferers. Pollen forecasts are categorised as low, moderate, high and very high, and most sufferers will start to experience symptoms when the forecast reaches the 'moderate' category (30-49 pollen grains per cubic metre of air).8
Predominant symptoms of SAC include itchy, watery, burning eyes and the conjunctiva is injected and oedematous.9 Lid and periorbital oedema and papillary hypertrophy of the upper palpebral conjunctiva may also occur (Figure 1). The cornea is rarely involved but severe cases can develop dellen. Ocular symptoms are often accompanied by nasal and pharyngeal complaints. PAC is similar to SAC but tends to be chronic and less severe. Symptoms generally persist throughout the year, although they may vary from season to season. Vernal conjunctivitis is characterised by large papillae in the tarsal or limbal areas and is accompanied by intense itching, photophobia and sometimes pain.7
Both the seasonal and the perennial conditions can usually be managed with topical ocular antihistamine and anti-inflammatory eye drops. Therapeutic approaches to SAC have traditionally been dominated by the use of preparations containing the mast cell stabiliser sodium cromoglycate, such as Opticrom. These topical agents are available as over-the-counter (OTC) pharmacy medicines for seasonal, prophylactic management, and as prescription-only medications for other allergic conditions, such as vernal and atopic conjunctivitis.10 However, a wide range of eye drops containing a variety of pharmacological agents is now available to treat ocular allergic symptoms,11 as well as a number of orally administered drugs.12

Allergy and CLwear
Regular allergy sufferers are less likely to be contact lens wearers; only 5 per cent wear contact lenses compared with 7 per cent of non-sufferers.4 However, many allergy sufferers are contact lens wearers and may experience the ocular symptoms of SAC, PAC or contact lens papillary conjunctivitis (CLPC), the type of GPC associated with contact lens wear. In fact as many as three out of four allergy-suffering contact lens wearers report some form of discomfort with lens wear.13
Contact lens wearers using chemical disinfection systems may also experience a hypersensitivity reaction resulting from the preservative in their lens solution.14 It is important to identify these solution-induced reactions which are best managed by switching the patient to a solution containing a different preservative, a peroxide-based system or, ideally, daily disposable lenses.
Eye care practitioners have an important role to play in the management of allergy-suffering contact lens wearers, since many can be easily and successfully managed in practice without the need for referral. Initial fitting and regular aftercare appointments provide practitioners with the opportunity to question patients about allergies, identify the signs and symptoms of allergic eye disease and offer appropriate advice.
If symptoms are managed appropriately, allergies such as SAC and PAC should not contraindicate contact lens wear. However, since 'prevention is better than cure' it is good practice to implement strategies that limit exposure of the eye to allergens.

CLperformance
Several studies have investigated the clinical performance of contact lenses in allergy sufferers. Kari et al15 found that a history of atopy increased five-fold the risk of experiencing symptoms during contact lens use and concluded that wearing time should be limited during the allergy season. A separate study compared tolerance to different kinds of contact lenses in young atopic and non-atopic wearers over one year of lens wear.16 Fewer atopic wearers described their lenses as very comfortable, but soft lenses were more comfortable than rigid lenses in this group. Other authors have found differences in clinical performance between different soft lens types when used by allergy sufferers.17
More recently, Lemp18 reported that with careful attention to recognising ocular allergy, regular monitoring and good compliance, successful contact lens wear could be achieved by most patients. This author stressed the need for clean lenses with minimal deposit build-up and advocated the use of either daily wear lenses with strict disinfection and cleaning procedures, or daily disposable lenses.
Opinions differ on the need to discontinue or reduce contact lens wear during the peak allergy season. Temporarily discontinuing lens wear may aid more rapid resolution, but is not usually necessary. Some authors suggest that, provided the cornea is not involved, the level of lens wear should be determined by the severity of the condition and the effect, if any, that treatment will have on contact lens use.19 Others have suggested that although allergens can bind to the surface of the lens, soft contact lenses may actually act as a barrier to reduce allergen exposure in the sensitive limbal area and surrounding conjunctiva.20
Attitudes to patients continuing contact lens wear while using anti-allergy eye drops also vary. Lemp18 advises against the use of anti-allergy agents when the lenses are in place but other authors suggest that even drops where contact lens use is contraindicated may be safely used for short durations while lenses are worn.21 If drops are to be instilled during soft contact lens wear, daily disposable lenses may be the best lens option for minimising the accumulation of preservatives over time or with repeated use.
Some clinicians advocate using drops twice daily, before lens insertion and after removal, to avoid preservative uptake. Although this is problematic where the recommended dosage is more than twice a day, as with some of the mast-cell stabilisers, other anti-allergic preparations Ð such as the OTC eye drop Livostin direct Ð can be used in this way.10
Overall, the consensus today would seem to be that, with the optimum choice of lenses and wearing schedule, and, where necessary, appropriate medication, all but the most severely affected contact lens wearers can continue to wear their lenses through the worst of the allergy season.

Management strategies
Various prescribing strategies can be used for managing allergic eye disease in contact lens users without suspending lens wear. These may either involve reducing exposure of the eye to allergens or introducing therapeutic measures to alleviate symptoms (Table 2).
Epstein20 suggests increasing lens replacement frequency during the peak season, switching to preservative-free or 'no rub' lens care products, the use of daily cleaners and re-wetting drops, warm compresses and lid massage. He advocates the use of mast-cell stabilisers for several weeks prior to the start of the allergy season. Krohn13 also recommends changing to a different soft lens material.
However, the use of daily disposable lenses, which eliminate care products and minimise exposure to allergens and irritants that can accumulate with repeated use of a single pair of lenses, has been described as the best alternative for allergy sufferers.13
Several studies have explored some of the differences between the daily disposable modality and conventional replacement modalities among a general population of lens wearers.22-26 In a three-year prospective study comparing the clinical performance of daily disposable and conventional daily wear contact lenses, the daily disposable lens users were more likely to be asymptomatic, reported fewer symptoms of redness, grittiness/dirty sensation, and had fewer lens surface deposits than conventional daily wear subjects.22
Daily disposable contact lens wearers experience improved comfort, better vision, increased wearing time and fewer unscheduled visits when compared with those using conventional daily wear soft lenses.24-26 1-Day Acuvue contact lenses (Johnson & Johnson Vision Care) have recently been shown to be an effective option for managing self-identified sufferers of dry, sensitive or easily irritated eyes.27 These findings suggest that daily lens replacement may also be a successful strategy for reducing complaints and symptoms among allergy-suffering contact lens wearers.

Allergy indication
The US Food and Drug Administration (FDA) has approved labelling clearance for two daily disposable lens types regarding possible relief from some symptoms associated with seasonal allergic conjunctivitis, and improved comfort for many patients who experience mild discomfort and itching associated with allergies during contact lens wear.28,29
Two recent studies have investigated the use of daily disposables among allergy sufferers. In 2001, Stiegemeier and Thomas6 reported that seasonal allergic conjunctivitis sufferers experienced fewer symptoms of burning and redness, and fewer symptoms overall, when wearing nelfilcon A daily disposable lenses than when wearing their habitual lenses.
More recently, Hayes et al30 conducted a large, multi-site study to evaluate subjective comfort and slit-lamp findings with 1-Day Acuvue among allergy-suffering contact lens wearers, during periods when allergen levels were elevated. This study also investigated the types of symptoms experienced by allergy sufferers and how they managed their condition.

Study design
The study was a 128-subject, bilateral, crossover, dispensing evaluation involving one month of single-use daily wear with 1-Day Acuvue and one month of daily wear with a new pair of patients' habitual, re-usable lenses replaced to their usual replacement schedule. A majority of patients replaced their habitual lenses fortnightly (46 per cent) or monthly (35 per cent) and most (83 per cent) used preserved solutions. Investigators were selected from 14 practices in the US from areas representing the potential for medium to high pollen count conditions at the time of the year the study was conducted. Pollen counts were obtained for each site one week prior to and twice weekly during the study.
Patients were surveyed for the presence of signs and symptoms related to allergy before the study and ocular itching, described as the 'hallmark symptom' of allergic conjunctivitis,31 was included as a recruitment criterion. Specific signs and symptoms experienced by the patient, their degree and severity, and stimuli and/or seasonal factors that influenced them were all recorded prior to the study.
At each of the 30-day follow-up visits, patients were examined on the slit lamp then asked to compare the comfort of the study lenses they had worn during the past month to that of their habitual lenses. Information on the use of medication and re-wetting drops was also collected.

Symptoms reported
All of the patients recruited to the study reported that they experienced itchy eyes when suffering from allergies and all reported reduced comfort with their contact lenses while suffering from allergies. Just over half (56 per cent) found that wearing contact lenses was difficult when taking allergy medications.
Eight out of 10 patients said they were affected by chronic allergy symptoms all year round and around half (54 per cent) said they responded to allergens not related to time of year. With respect to seasonal symptoms, almost all (99 per cent) experienced allergies triggered by pollen and said their allergies occurred at a specific time of the year (94 per cent). Around seven out of 10 (72 per cent) reported suffering from hay fever. In terms of specific eye symptoms, most patients experienced allergy-related redness (97 per cent), watery eyes (87 per cent) and burning and stinging (89 per cent).

Use of medication
At the start of the study, just over half of the patients (55 per cent) were using medications, other than OTC and/or prescription ocular medication, for their allergies and 61 per cent of these subjects reported taking medications on a daily basis when experiencing allergies. When surveyed about their habits prior to the study, 60 per cent said they took prescription medications and 73 per cent took OTC medications.
Around half (55 per cent) stated they took medications specifically to relieve their ocular symptoms while suffering from allergies and a similar proportion (53 per cent) reported using re-wetting drops at intervals ranging from 1-3 times per week to several times per day.

Comfort and slit-lamp results
Two out of three of the allergy sufferers (67 per cent) agreed that the 1-Day Acuvue lenses provided improved comfort when compared to the lenses they wore prior to the study, compared with 18 per cent agreeing that a new pair of habitual lenses provided improved comfort (Figure 2).
More subjects agreed that the test lenses provided improved comfort compared to their usual lenses than when compared to a new pair of their habitual lenses, and this difference was statistically significant (P