Ocular allergy is a common and significant problem. As much as 20 percent of the general population in the United States, or 50 million people, may suffer from allergic conjunctivitis. Without proper treatment, patients, particularly contact lens wearers, may face a major disruption of their work, productivity and daily functioning. This article will review ocular allergy in this population and address ways that ophthalmologists can alleviate their symptoms.

Background
Most people who develop ocular allergies do so in childhood. A small group develops ocular allergies between the ages of 18 and 35. The causes may be: environmental, genetic, related to medication or cosmetics, or related to medical devices such as sutures.

Ocular allergies are a heterogeneous group of conditions that primarily affect the conjunctiva. There are multiple mechanisms for the allergic reaction, including IgE and IgG Type 1 mediated hypersensitivity, as well as delayed Type IV hypersensitivity.


Ocular allergies include: acute allergic conjunctivitis; seasonal allergic conjunctivitis (hay fever); perennial allergic conjunctivitis; atopic keratoconjunctivitis, vernal keratoconjunctivitis; giant papillary conjunctivitis; and contact allergies.

Acute allergic conjunctivitis is the most prevalent of the ocular allergies. It occurs suddenly, and the symptoms of acute conjunctival hyperemia and edema, lid edema associated with watery discharge and tearing can develop rapidly. It generally clears within 24-48 hours after the offending allergen is removed.

Seasonal, or hay fever, allergic conjunctivitis (SAC) is also common, affecting 10 to 15 percent of the population. It may be associated with allergic rhinitis, and there is usually a family or personal history of atopy. SAC is often a response to a specific pollen, for example, grass in the spring, ragweed in the fall and tree pollen in winter. The signs and symptoms are similar but may be less dramatic than those of acute allergic conjunctivitis.

Acute allergic conjunctivitis develops rapidly and resolves soon after contact with the allergen ends.

Perennial, or chronic, allergic conjunctivitis, as the name suggests, may occur year-round and is triggered by environmental allergens such as dust, mites and animal dander.

Allergic rhinitis is most common chronic allergic disease, affecting nearly 35 million Americans. It leads to 8 million office visits, 3.5 million lost work days and 2 million lost school days each year. Some 60 percent of allergic rhinitis patients suffer allergic conjunctivitis.

Allergic conjunctivitis is a Type I anaphylactic hypersensitivity. Allergen proteins dissolve in the tears and bind to IgE antibodies that are attached to the mast cells. This causes mast cell degranulation, followed by the release of chemical mediators, which are responsible for the signs and symptoms.
The acute phase is attributed to mast cell degranulation and the release of preformed mediators such as histamine. The late phase, occurring three to 12 hours after the initial reaction, may be caused by eosinophils, neutrophils and newly formed mediators.

Treatment of allergic conjunctivitis begins by trying to avoid the allergen, if it can be identified. This may involve use of air conditioning and filtration devices, and/or using pillows and bed clothes that reduce the exposure to allergens. In more severe cases especially in those associated with systemic allergic manifestations, immunotherapy may be considered. Non-steroidal anti-inflammatory drugs, antihistamines, mast cell stabilizers or combination mast cell stabilizer/antihistamine products can also be considered as treatment options. Topical steroids are rarely necessary.

Contact Lens Wearers
Atopic contact lens wearers are more likely to have ocular symptoms, (58 percent to 33 percent)1 than non-atopic contact lens wearers. The frequency of eye symptoms has been estimated to be 2 to 2.5 times greater in allergic contact lens wearers than non-allergic contact lens wearers. Contact lens wearer who also have rhinoconjunctivitis are more likely to experience absolute or partial contact lens intolerance2 compared to individuals who do not have this condition.

The incidence of Giant Papillary Conjunctivitis is higher and the symptoms appear to be more severe with soft lenses than with rigid lenses.

As with non-contact lens wearers, avoidance of the allergen is the first defense. In some cases, discontinuance of lens wear or reduction of wearing time during the allergy season may be warranted.

The availability of frequent replacement lenses has expanded the options for these patients. Switching a patient to a more frequent replacement schedule, including daily disposable contact lenses, may improve comfort. A more frequent replacement schedule leads to reduced lens coating and a decreased antigen load.

Medical management, with antihistamines, mast cell stabilizers or combination products may also be effective, though steroids should be avoided for contact lens wearers. The use of mast-cell stabilizers or a combination mast-cell stabilizer/ antihistamine may enable patients with ocular allergies to wear their contact lenses during the allergy season. (Tauber J. Nedocromil Sodium 2% Ophthalmic Solution vs. Artificial Tears Used Twice Daily in Patients with Contact Lens Intolerance and a History of Allergic Conjunctivitis [abstract]. 2002 Annual Meeting, Association for Research in Vision and Ophthalmology. Abstract 116.)

GPC Still a Concern
Giant Papillary Conjunctivitis may occur with ocular prostheses, sutures, scleral buckles or adhesives, or with any type of contact lens. The symptoms include decreased lens tolerance, increased lens movement, increased mucus, blurred vision and ocular itching.

Examination of the superior tarsal conjunctiva will reveal tarsal injection, visible loss of the vascular pattern and papules greater than 0.3 mm. In the more severe cases, the bulbar conjunctiva may be involved and there may be a superficial punctate keratopathy. In addition, apical staining of the papules with fluorescein may be noted. Almost all patients report significant coating of the contact lens.

The incidence of GPC (85 percent) is higher with soft lenses than with rigid lenses (15 percent). The symptoms of GPC appear to be more severe with soft lenses than with rigid lenses. GPC is more common in atopic individuals (history of environmental, medication or food allergy than the non-GPC subjects.)

This condition also appears to peak in the late spring and early fall, which corresponds to the height of the allergy season.3 GPC is thought to be an immunologically mediated condition; locally produced tear immunoglobulins have been found in the tears of GPC patients. The tear levels return to normal when the contact lens is removed, and the symptoms abate.

Trauma is also a factor in the pathophysiology of GPC. Neutrophil chemotactic factor has been found in high concentrations in the tears of GPC patients. As the antigen-coated contact lens traumatizes the tarsal conjunctiva, the ocular immune system releases inflammatory mediators, which leads to the attraction of inflammatory cells such as neutrophils, basophils, eosinophils and mast cells. These cells react with immunoglobulins to cause the release of vasoactive amines that are responsible for the signs and symptoms of GPC.4

While the introduction of frequent replacement contact lenses has helped to manage patient with GPC, this condition still occur with frequent replacement lenses. One study showed a 21-percent incidence of GPC among subjects fitted with frequent replacement contact lenses, on the average 23 months after the initial fitting. However none of the subjects wearing contact lenses replaced on a daily, one-week or two-week replacement schedule developed GPC. The majority of patients who developed GPC were on a four-week or greater replacement schedule.5

GPC Treatment
The signs and symptoms will guide the choice of treatment for contact-lens related GPC. Patients with mild signs and symptoms, should discontinue lens wear for one to two weeks. Consider changing the lens replacement cycle for these patients to four-weeks or less, and monitor the patient every three months.

Moderate levels of GPC will call for a two- to four-week discontinuance of lens wear, to allow any apical staining or superficial punctate keratitis to resolve. These patients will benefit from a daily-disposable contact lens at a maximum replacement schedule of one to two weeks.

For severe cases, discontinue lens wear for a minimum of four weeks, or until the tarsal inflammation resolves. The papillary reaction will not abate during this period. These patients should be switched into a daily disposable lens and followed every two to three months. If GPC recurs, contact lens wear should be discontinued until the signs of inflammation have resolved. The patient should be fitted with a daily disposable lens and a mast-cell stabilizer (q.i.d. dosing)6 or a mast-cell stabilizer/antihistamine combination product (b.i.d) should be prescribed for one to three months. The drug can then be slowly tapered depending on the clinical response.

The increasing array of options in both contact lens modalities and pharmaceutical agents to treat ocular allergy is greatly improving the comfort and viability of lens wear for our allergic patients. It’s incumbent on us to be familiar with these options and to guide our allergic patients to the lens and treatment choices that will maximize their contact lens wear. 

Dr. Donshik is a clinical professor of ophthalmology at the University of Connecticut and is in private practice.

1. Kari O, Haahtela T. Is atopy a risk factor for the use of contact lenses? Allergy 1992:47:295-8.
2. Kumar P, Elstone R, et al. Allergic Rhinoconjunctivitis and Contact Lens Intolerance CLAO J1991: 17;31-34.
3. CG, Riggle A, Tuel JA. Association of Giant Papillary Conjunctivitis with Seasonal Allergies. Optom Vis Sci 1990:67;192-195.
4. Donshik P. Giant Papillary Conjunctivitis. Trans of the Am Ophthalmol Soc 1994:92;687-744.
5. Donshik p, Porazinski A. Giant Papillary Conjunctivitis in Frequent-Replacement Contact Lens Wearers: A Retrospective Study. Tr Am Ophth Soc 1999; 97:205-220.
6. Kruger CJ, Ehlers WH, et al. Treatment of Giant Papillary Conjunctivitis with Cromolyn Sodium. CLAO J 1992:18;46-48.