This finding could help develop new eye treatments for humans and animals, researchers say.

“Discovering how tears can maintain homeostasis in different species and environmental conditions is key to understanding evolution and adaptation. It is essential for the discovery of new molecules for ophthalmic medicine, ”said Arianne P. Oriá, as‌sociate professor of veterinary science at the Bahia Federal University, Salvador, Brazil.

Over the past few years, Oriá has spearheaded efforts to study the tears of various animals, including reptiles and birds. In the latest report, this scientist provides insight into the tears of seven species of birds and reptiles.

"Although birds and reptiles have different structures responsible for the production of tears, some of the components of this liquid have concentrations similar to those found in humans," Oriá added. The crystal structures are organized in different ways so that they ensure eye health and equilibrium with different environments ”.

With the support of veterinarians and caregivers at the conservation and wildlife care centers, researchers collected tears from healthy captive animals, including parrots. long tailed, hawk, owl, parrot, tortoise, caiman crocodile and sea turtle.

When scientists analyzed the chemical composition of tears, they found that the level of electrolytes, such as sodium and chloride, was similar to the concentration of electrolytes present in human tears. However, the researchers measured slightly higher levels of urea and protein in the tears of owls and sea turtles.

Besides, researchers have also studied crystals that form when tears dry up. In addition to accurately identifying differences in tears, crystalline patterns can also reveal the presence of various eye diseases. Despite the similar chemical composition, the tears of different birds and reptiles show a surprising amount of variation.

In it, the crystalline patterns observed in the tears of sea turtles are particularly unique. They must produce special tears to protect their underwater eyes.

In the future, scientists hope to be able to study the tears secreted by wild animals.

"This knowledge helps in understanding the evolution and adaptation of these species, as well as in their conservation," Oriá emphasized.