Ocular allergy - an overview

Ocular allergic eye disease is common, affecting up to 20% of the world's population and nearly all people have experienced some type of allergy in their lifetime. The clinical presentation of the various form of ocular allergy can vary greatly, from mild symptoms unaccompained by ocular signs, to severe disease with vision-threatening complications.

There are four main types of allergic eye disease: allergic conjunctivitis, vernal keratoconjunctivitis, atopic keratoconjunctivitis and giant papillary conjunctivitis. There exist both an early and late phase of the ocular allergic reaction. Seasonal and perennial allergic conjunctivitis, that affect 90% of ocular allergy sufferers, are primarily the consequence of early phase reactions. More rarely seen diseases such as atopic keratoconjunctivitis, vernal keratoconjunctivitis and giant papillary conjunctivitis are result of much more complex ocular late phase reactions.

Although an IgE-mediated immediate hypersensitivity reaction has been demonstrated or postulated in many types, the pathophysiology underlying the allergic conjunctivitides is not fully understood. Great variety of available pharmacologic options is an evidence of complexity of the chemical reactions associated with mast cell degranulation and mediator release causing the onset of allergic signs and symptoms.