**7. Conclusions**

Iron is one of the most common elements on Earth. Two-hundred years ago, it was discovered that, after desiccation, the residual ashes of an aged human retina could be mobilized by a magne<sup>t</sup> (as quoted in [191]). Nowadays the chemical study of iron structure and its outer electrons has been revealed by the discovery of quantum effects of iron electron in biology. The best illustrations have been described by Cedric Weber who demonstrated that very specific quantum effects are involved to explain the energy in the binding of iron to oxygen and CO to hemoglobin [192]. This transition metal plays a main role in retinal physiology, but overload leads to retinal degeneration and loss of function. Iron chelation is a potential therapeutic target to prevent retinal degeneration. TF, as an endogenous iron binding protein, avoids toxic effects of iron depletion and activates additional neuroprotective pathways.

**Author Contributions:** Conceptualization: E.P., Y.C., F.B.-C.; literature search: E.P., A.D.; J.Y., Y.C., F.B.-C.; figure and tables: E.P., J.Y.; writing—original draft preparation E.P., A.D.; Y.C., F.B.-C.; writing—review and editing: E.P., A.D.; Y.C., F.B.-C. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Acknowledgments:** We sincerely thank Jean-Claude Jeanny and Marina Yefimova for their significant contribution in the initial description of iron and iron-related proteins in retina.

**Conflicts of Interest:** Y.C., E.P. and F.B.C. are cited as inventor on a patent for the use of transferrin for the treatment of eye diseases.
