RBP3 and retinal degeneration: We speculate that the different roles of IRBP on myopia and retinal degeneration may involve different ligands (perhaps including retinoic acid) bound to IRBP early in development that drive myopia and eye size, whereas the later effects of IRBP in preventing retinal degeneration may involve a different set of the ligands (including all-trans-retinol and 11-cis-retinal) integral to the vitamin A cycle.