Visual disorders affect more than 30 million people in the United States. It is becoming increasingly clear that abnormal retinal function in adults can be associated with dysfunction of cell-cell signaling. Errors in this information transfer process, arising from mutation in essential signal transduction molecules, can lead to a variety of pathologies, including developmental defects, retinal degeneration, and cancer. Our research concentrates upon understanding these questions in the Drosophila eye. It is clear that many of the genes and mechanisms that they harness are totally conserved between Drosophila and humans. Thus, discoveries we make in fruit flies will hopefully lead to new clues about the homologous processes in humans. This will contribute to our further understanding of visual pathologies and the means to treat and cure them.