Neurotrophin Fluid/Tissue Technique Reported Disease state References NGF Serum ELISA Increase DR/PDR [45] NGF Tear ELISA Increase DR/PDR [45] NGF Serum ELISA Increase DN [47] NGF Aqueous humor Immunoblot Decrease PDR [49,50] NGF Vitreous fluid Immunoblot Decrease DR [49,50] NGF Serum Immunoblot Decrease Pdr [50] proNGF Aqueous humor Immunoblot Increase PDR [49,50] proNGF Vitreous fluid Immunoblot Increase DR [49] proNGF Serum Immunoblot Increase Pdr [50] BDNF Serum ELISA Decrease NPDR, PDR [51] BDNF Vitreous Elisa Decrease Npdr, Pdr [51] BDNF Serum ELISA Decrease PDR [52] NT3/NT4 Vitreous fluid/Serum Immunoblot Increase PDR [11]

DN: Diabetic Neuropathy; DR: Diabetic Retinopathy; PDR: Proliferative Diabetic Retinopathy; NPDR: Non-Proliferative Diabetic Retinopathy

Table 1: A summary of studies that determined the level of neurotrophins in the eyes of diabetic patients.