Curve Ball

Magnifying glasses are thicker in the centre, and thinner around the edge. Each unit of a fruit fly eye has a similarly shaped corneal lens to bend and focus light. To understand how this biconvex shape is produced, researchers examined the role of a main component: chitin. Chitin is secreted by cells and helps form a scaffold between cells. Reducing production made lenses thinner and less curved. If production was increased specifically in cells at the edges of the lens (pictured, chitin in green), just the periphery thickened. The results show that the natural shape results from relatively high levels of chitin produced by central cells, and illustrates that organ shape can be sculpted not just by cells themselves, but also by the extracellular matrix between them. Although not produced in humans, chitin is used in biomedicine, so understanding how such scaffolds support biological structures could inform biomaterial design.

Image made using Leica Microsystems microscopy

Written by Anthony Lewis

Anthony Lewis

Writer

Ant was the web editor in the early days of BPoD, and has since worked with the UK’s top science organisations as a writer and multimedia producer. He now splits his time between freelance work and managing multimedia at The Lancet.

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• Image from work by Neha Ghosh, Eva Rojo-Iost and Jessica E. Treisman
• Department of Cell Biology, NYU Grossman School of Medicine, New York, NY, USA
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in PLOS Biology, March 2026