Retinal calcium waves coordinate uniform tissue patterning of the <i>Drosophila</i> eye

Optimal neural processing relies on precise tissue patterning across diverse cell types. Here, we show that spontaneous calcium waves arise among non-neuronal support cells in the developing <i>Drosophila</i> eye to drive retinal morphogenesis. These waves are initiated by Cad96Ca receptor tyrosine kinase signaling, triggering phospholipase C-γ-mediated calcium release from the endoplasmic reticulum. A cell type-specific "innexin code" coordinates wave propagation through a defined gap junction network among non-neuronal retinal cells, excluding photoreceptors. Wave intensity scales with ommatidial size, triggering stronger myosin II-driven apical contraction at interommatidial boundaries in larger ommatidia. This size-dependent mechanism compensates for early boundary irregularities, ensuring uniform ommatidial packing that is critical for precise optical architecture. Our findings reveal how synchronized calcium signaling among non-neuronal cells orchestrates tissue patterning in the developing nervous system.