In this work, we for the first time report the identification of UV filters in the bird eye lens. We found that lenses of some raptors (black kite, common buzzard) and waterfowl (birds from Podicipedidae family) contain unusually high levels of reduced nicotinamide adenine dinucleotide (NADH)—a compound with high absorption in the UV-A range with a maximum at 340 nm. The lens metabolome of these birds also features an extremely low [NAD +]/[NADH] ratio. Chemometric analysis demonstrates that the differences between the metabolomic compositions of lenses with low and high NADH abundances should be attributed to the taxonomic features of bird species rather to the influence of the low [NAD +]/[NADH] ratio. We attributed this observation to the low metabolic activity in lens fiber cells, which make up the bulk of the lens tissue. Photochemical measurements show that properties of NADH as a UV filter are as good as that of UV filters in the human lens, including strong absorption in the UV-A spectral region, high photostability under both aerobic and anaerobic conditions, low yields of triplet state, fluorescence, and radicals under irradiation. Lenticular UV filters protect the retina and the lens from photo-induced damages and improve the visual acuity by reducing chromatic aberrations; therefore, the results obtained contribute to our understanding of the extremely high acuity of the raptor vision.

在这项工作中，我们首次报告了鸟眼镜头中紫外线过滤器的识别。我们发现一些猛禽（黑鸢、普通鵟）和水禽（鲇科鸟类）的镜片中含有异常高水平的还原型烟酰胺腺嘌呤二核苷酸 (NADH)——一种在 UV-A 范围内具有高吸收性的化合物，最大值为340 纳米。这些鸟类的晶状体代谢组还具有极低的 [NAD +]/[NADH] 比率。化学计量分析表明，具有低和高 NADH 丰度的镜片的代谢组学组成之间的差异应归因于鸟类物种的分类学特征，而不是低 [NAD +]/[NADH] 比率的影响。我们将此观察结果归因于构成晶状体组织大部分的晶状体纤维细胞的低代谢活动。光化学测量表明，NADH 作为紫外线过滤剂的特性与人类晶状体中的紫外线过滤剂一样好，包括在 UV-A 光谱区域的强吸收、有氧和厌氧条件下的高光稳定性、低三重态产率、荧光和辐射下的自由基。透镜状紫外线滤镜保护视网膜和晶状体免受光致损伤，并通过减少色差提高视力；因此，获得的结果有助于我们了解猛禽视力的极高敏锐度。和辐射下的自由基。透镜状紫外线滤镜保护视网膜和晶状体免受光致损伤，并通过减少色差提高视力；因此，获得的结果有助于我们了解猛禽视力的极高敏锐度。和辐射下的自由基。透镜状紫外线滤镜保护视网膜和晶状体免受光致损伤，并通过减少色差提高视力；因此，获得的结果有助于我们了解猛禽视力的极高敏锐度。