Photomicrographs demonstrating FLT-1 immunostaining of non-diabetic retina (A), diabetic retina with no obvious retinopathy (B), diabetic retina with obvious intraretinal vascular changes but no evidence of PDR (C), the same retina stained with GFAP (D), diabetic retina with PDR (E, F, G), diabetic retina post laser but with no residual PDR (H). Immunostaining for FLT-1 was greatest in the diabetic tissue compared with non-diabetic tissue. Increased staining was generally confined to the inner nuclear layer and the ganglion cell layer. Magnification A, G ×94; B, C, E ×118; D ×156; F ×378; H ×236.