Trends in Prevalence and Treatment of Ocular Allergy

Paulo J. Gomes


Curr Opin Allergy Clin Immunol. 2014;14(5):451-456. 

In This Article

Abstract and Introduction


Purpose of review This review describes recent findings and trends in prevalence and treatment of allergic ocular diseases. Although the major focus is on seasonal and perennial allergic conjunctivitis, related disorders will also be considered.

Recent findings Published reports from countries around the world suggest that the spectrum of atopic diseases, including seasonal and perennial allergic conjunctivitis, is continuing its pattern of increasing prevalence, which has been well documented over the past few decades. In addition, although treatment modalities have focused on topical formulations including antihistamines and corticosteroids, there is a significant emphasis on immunotherapy as an alternative treatment modality, particularly in the USA.

Summary Allergic conjunctivitis is a key component in the spectrum of allergic diseases that is sometimes collectively referred to as rhinoconjunctivitis. Because of its high prevalence worldwide, it exacts an increasing toll in terms of patient discomfort, morbidity, and loss of productivity. Current estimates suggest that at least 20% of the overall population suffers from some form of allergic conjunctivitis, many without ever seeking treatments. In addition, a significant proportion of patients experience chronic forms of allergy that are less responsive to existing therapies. Recent approval of immunotherapy-based treatments may address this therapeutic gap.


Ocular allergy includes a spectrum of disorders with an overlapping symptomology and progressive severity; these disorders include seasonal allergic conjunctivitis (SAC) and perennial allergic conjunctivitis (PAC), atopic keratoconjunctivitis (AKC), and vernal keratoconjunctivitis (VKC). A fifth disorder, giant papillary conjunctivitis, shares some of the symptomologies of other allergic eye diseases but is primarily the result of contact lens misuse.

SAC and PAC (collectively, allergic conjunctivitis) are the most common forms of ocular allergy. Most recent estimates suggest that 15–25% of the US population, or between 50 and 85 million Americans, suffer from allergic conjunctivitis or some form of ocular allergy.[1–3] The prevalence of allergic conjunctivitis is similar in Europe, Japan, and Australia, and is increasing worldwide.[4] Although they are not life threatening, the symptoms of ocular allergy experienced by affected individuals have a significant impact on the productivity and quality of life.[5,6] More severe forms of the ocular allergy such as AKC or VKC are rare, but can be sight threatening.[7,8] In addition, they provide pathophysiological clues that help to address more common forms of ocular allergic disease.

Triggers for allergic responses include pollens, animal dander, mold spores, and other environmental allergens. Similarly to other allergic conditions, allergic conjunctivitis may include both an early, acute phase triggered by mast cell degranulation and a late, chronic phase involving allergic inflammation.[9] Symptomology is initially driven by histamine receptor activation, whereas the delayed phase is because of a combination of proinflammatory mediators and the infiltration of immune cells such as neutrophils, basophils, and eosinophils.[10]

AKC is a severe form of allergic ocular disease most often seen in patients 30–50 years old with multiple systemic atopic diseases; patients with AKC typically have allergic dermatitis, eczema, and allergic asthma.[7] The disease is symptomatically comparable to severe, chronic PAC, with additional symptoms including corneal involvement. The chronic nature of the disease and its associated atopic comorbidities lead to a high rate of steroid-induced complications, including cataracts and glaucoma.

VKC is a severe form of ocular allergy that preferentially affects boys between 5 and 15 years of age, living in equatorial countries:[8,11] The disease typically presents initially in the spring allergy season, but then can recur at any time of year. Two features that are classically diagnostic for VKC are tarsal papillae and limbal gelatinous infiltrates.