This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
All of the following take part in the pathogenesis of macular edema in diabetic retinopathy except – 
Select and explain. 
A. Retinal pigment epithelium dysfunction, B. Oxidative stress, C. VEGF, D. Increased protein kinase–C
A: Retinal pigment epithelium dysfunction
Answer: A: Retinal pigment epithelium dysfunction 
Explanation: Etiopathogenis of diabetic retinopathy (including macular edema) 

Following factors are important in development of diabetic microangiopathy, which is responsible for the development of retinopathy :-


Activation of protein kinase C
Oxidative stress
Increased production of growth factors, amongst which Vascular endothelial growth factor A (VEGF-A is the most important). Other factors are TGF - β, PDGF, EGF and IGF