For a brief period during development, fruit flies experience waves of calcium moving through the cells in their eyes. According to a study published in Science by researchers at New York University, these waves help cells communicate and shape the structure of the eye.
Scientists have previously observed similar calcium waves in the developing retinas of humans and other mammals. These occur before vision begins and are thought to refine connections in the visual system. However, their role in forming the physical structure of the eye had not been explored until now.
The NYU research team found that fruit flies also exhibit these “retinal waves” during eye development. The synchronized activity helps create an ordered architecture necessary for vision.
“This discovery uncovers a universal developmental mechanism where synchronized calcium activity shapes tissues to achieve precise sensory function,” said Ben Jiwon Choi, postdoctoral fellow at NYU’s Department of Biology and lead author of the study.
“Our study shows that these long-seen retinal waves, in addition to coordinating neuronal circuitry, also play a key role in shaping the developing eye,” said Claude Desplan, professor of biology and neural science at NYU and senior author on the paper.
Fruit flies are widely used as model organisms because they share about 75 percent of genes linked to human diseases. In this study, researchers observed that retinal waves begin when calcium is released from stores inside cells. The signal then spreads across supporting cells via gap junctions—channels connecting neighboring cells. Unlike typical neural activity marked by calcium signaling in neurons, these retinal waves occur in non-neuronal cells responsible for building eye structure.
The research demonstrated that retina-wide patterns generated by these waves sculpt the surface of the fly’s eye, resulting in uniform architecture needed for accurate vision.
“These retinal waves appear to determine the shape of the eye itself and prepare the eye to be able to see later on,” Desplan said.
The team also noticed that activity was stronger toward the lower part of each fly’s compound eye—the area facing downward toward less light. This leads to larger lenses developing there compared with smaller lenses on top.
“These waves allow the eye, which develops in a very fixed manner, to adapt the shape of its different parts that see the sky or the ground,” added Desplan.
Other contributors include Yen-Chung Chen. Funding came from several sources including grants from National Institutes of Health (EY13010, EY017916, F32EY027682), NYU’s MacCracken Fellowship program, New York State Stem Cell Science program (NYSTEM), and Taiwan Ministry of Education.
