The regulation of the expression of the Retinal Determination (RD) genes is central in eye development. Mis-regulation and mutations affecting RD genes severely affect eye development and cause congenital diseases. Most studies on eye development have focused on gene regulation during transcription. MicroRNAs (miRNAs) belong to a class of small regulatory RNAs with the potential to regulate the expression of many genes at post-transcription. Using D. melanogaster, this body of work examines the importance of miRNAs and posttranscriptional regulation of the RD gene eyes absent (eya) in forming the neurocrystalline lattice of compound eye. This work characterizes the compound eye defects arising from the absence of miRNAs. It also provides evidence that a specific miRNA is capable of inducing eya expression, while unexpectedly reducing eya mRNA level. This is contrary to the widely believed function of miRNAs in repressing translation. Finally, this study also shows that EYA has roles in DNA damage response in order to preserve genome integrity and promote cell survival. Through a genetic screen and subsequent validation, this work presents a link between microRNAs, EYA and the DNA damage response.