Intelligent Design (ID) argues for the existence of a designer, postulating it as a theoretical entity of a scientific theory aiming to explain specific characteristics in nature that seems to show design. It is commonly accepted within the Scientific Realism debate, however, that asserting that a scientific theory is successful is not enough for accepting the extramental existence of the entities it postulates. Instead, scientific theories must fulfill additional epistemic requirements, one of which is that they must show successful novel (...) predictions. Evolutionists typically attack ID by offering cases of bad design, such as the inverted retina of vertebrates. ID defenders defend their position affirming that the inversion of the retina must be a detail of design for an as of yet unknown function. The recent discovery of such a function is celebrated by ID defenders as a triumph over evolutionists. The inverted retina case is a good candidate for a novel prediction in favor of ID. In this paper, I analyze whether this is the case. (shrink)