Spring catarrah is -
It is considered a hypersensitivity reaction to some exogenous allergen, such as grass pollens. VKC is thought to be an atopic allergic disorder in many cases, in which IgE-mediated mechanisms play an impoant role. Such patients may give personal or family history of other atopic diseases such as hay fever, asthma, or eczema and their peripheral blood shows eosinophilia and inceased serum IgE levels. Ref: A K KHURANA COMPREHENSIVE OPHTALMOLOGY,E4,page-74
Type I hypersensitivity reaction
Type II hypersensitivity reaction
Type III hypersensitivity reaction
Type IV hypersensitivity reaction
Conjunctiva