Introduction 3. Canonical Wnt Signaling 4. Non-canonical Wnt Signaling 5. Modulators of Wnt/Fzd Signaling 6. Drosophila Eye Development 6.1. Generation of the optic primordium 6.2. The structure of the adult Drosophila eye 6.3. Differentiation of the adult eye 7. Wingless/Fz Signaling and Drosophila Eye Development 7.1. Wingless limits the size of the Drosophila eye field and regulates retinal cell proliferation 7.2. Wingless regulates progression of the morphogenetic furrow 7.3. Wingless regulates dorsoventral polarity of the developing eye 7.4. Wingless signaling shapes the pupal eye 8. Vertebrate Eye Development 8.1. Lens induction and differentiation 8.2. Retinal differentiation 9. Wnt/Fzd Signaling and Vertebrate Eye Development 9.1. Wnt/Fzd signaling during eye specification 9.2. Wnt/Fzd expression during vertebrate lens development 9.3. Role of Wnt/Fzd signaling in lens development 9.4. Wnts/Fzd expression during retinal development 9.5. Role of Wnt/Fzd signaling in retinal development 10. Human Ocular Disease and the WNT/FZD Signaling Pathway 11. Future Perspectives