The key to the exceptional night vision of the nocturnal helmeted gecko is a series of distinct concentric zones of different refractive powers, according to a study published in the online Journal of Vision. Nocturnal geckos are among the very few living creatures able to see colors at night. "We were interested in the geckos because they, and other lizards, differ from most other vertebrates in having only cones in their retina," said project leader Dr. Lina Roth of Lund University in Sweden. "With the knowledge from the gecko eyes, we might be able to develop more effective cameras and maybe even useful multifocal contact lenses." The nocturnal gecko’s multifocal optical system is comprised of large cones, which the researchers calculated to be more than 350 times more sensitive than human cone vision at the human color vision threshold. The nocturnal gecko’s optical system gives them an advantage because light of different ranges of wavelengths can be focused simultaneously on the retina. Another possible advantage is that their eyes allow them to focus on objects at different distances. Therefore, the multifocal eye would generate a sharp image for at least two different depths. Geckos that are active during the day do not possess the distinct concentric zones and are considered monofocal, the researchers said. [Press release] [Journal of Vision abstract]Login Or Register To Read Full Story