The mean levels of MANF in the vitreous samples from patients with proliferative diabetic retinopathy (n = 21) (3.44 ± 1.07 ng/ml) and retinal detachments (n = 16) (3.43 ± 1.09 ng/ml) were significantly higher than those in patients with macular holes (n = 18) (1.21 ± 0.28 ng/ml) (p < 0.001). This evidence concerns the gene MANF and proliferative diabetic retinopathy.