To test this, a group of engineers* removed the corneal lenses of blow flies, mounted them on brass and coated them with a fluorescent material. They excited the coating with UV light and measured the directional intensity of emission. Compared to a flat surface, the coated blow fly eye illuminated a wide angle much more uniformly.
Disgusted even though most people are with flies, we do not advocate the mass harvesting of flies to obtain corneas to make light sources of the kind we have investigated. Instead, an industrially scalable bioreplication technique can be used to make multiple replicas of just a few corneas, and the replicas can be coated with one or more fluorescent materials.*
We hope that our initial demonstration will pave the way for the development of bioreplicated light-emitting and light-detecting photonic devices.*
*Raúl J. Martín-Palma1, Amy E. Miller, Drew P. Pulsifer and Akhlesh Lakhtakia. (2014) Angular distribution of light emission from compound-eye cornea with conformal fluorescent coating. Appl. Phys. Lett. 105:103703.