This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Conjunctiva, Subject name: Ophthalmology
Spring catarrah is - 
Select and explain. 
A. Type I hypersensitivity reaction, B. Type II hypersensitivity reaction, C. Type III hypersensitivity reaction, D. Type IV hypersensitivity reaction
A: Type I hypersensitivity reaction
Answer: A: Type I hypersensitivity reaction 
Explanation: 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