POU4F1 and proliferative diabetic retinopathy: In contrast, results in the P23H-1 rat, a model of inherited photoreceptor degeneration, showed decreased dendritic arborization but increased coexpression of Brn3a and melanopsin31, while the PIPR was restored in eyes with non-proliferative diabetic retinopathy indicating the resistant character of GCs and ipRGCs46.