A new scientific study claims that “tears of birds and reptiles have a similar chemical composition to that of humans; a finding that may help scientists develop eyes treatment.”
On account of a new study, which found that birds and reptiles have the same chemical composition of humans, better eyes treatment could be developed. To conduct their new study, researchers from the Fedral University of Bahia (Brazil) contrasted the composition of the birds and reptiles’ tears in addition to their structural patterns when they dry out. To add new dimensions to their study, these researchers also examined birds and reptiles’ tears, which were not examined before, thus adding to the short list of mammals including humans, dogs, horses, camels, and monkeys.
Tears are important and play a vital role in keeping eyesight in a good condition across species. The team added: “although the tears were chemically similar, but they differ in their core structure.”
The team also clarified that the difference between the tears core structures is used to reveal different types of eye diseases and hence the best ways to develop treatments.
Professor Arianne P Oria, who started this study, point out that in order to understand how tears evolve, there should be a prior understanding of how they could sustain a steady, quite constant internal environment under different circumstances.
According to Oria this understanding is crucial for “the discovery of new molecules for ophthalmic drugs”.
In essence, tears are clear liquid hidden in the lacrimal glands found in the mammals’ eyes.
However, despite the importance of the tears in sustaining healthy eyesight, only few mammals’ tears have been subjected to study.
In order to conduct their new study, the team of researchers studied the liquid components of seven captive species of birds and reptiles.
These included macaws, hawks, owls, turquoise-fronted amazon (a type of parrot), as well as tortoises, caimans (a type of crocodile) and sea turtles.
In contrast, samples of tears were also collected from ten healthy human volunteers.
The results of the collected samples revealed the existence of similar amounts of electrolytes, such as sodium and chloride, although there were slightly higher concentrations in bird and reptile tears.
The researchers also examined the crystals that molded when the tear fluid dried out and they found some different structures form from different species tears.
The results also showed some differences in the arrangement of tear crystals between wild species and humans in spite of fact that all species had a similar tear composition.
What made the sea turtle and caiman samples more distinguished is the uniqueness of their tear crystals, which seem to be a result of an adaptation to their aquatic environment.
In contrast, human tears had thicker crystals as a result to changes brought by the increased presence of mucus or macromolecules, the team wrote.
Professor Oria pointed out that “although birds and reptiles have different structures that are responsible for tear production, some components of this fluid (electrolytes) are present at similar concentrations as what is found in humans”.
He also went on saying: “But the crystal structures are organised in different ways so that they guarantee the eyes' health and an equilibrium with the various environments”.
However, the team clarified that there is still a need for further studies with a wider range of species to understand more about the role of tears.
Professor Oria said: “This knowledge helps in the understanding of the evolution and adaption of these species, as well as in their conservation”.
This research was published in the journal Frontiers in Veterinary Science.
BY … Maiada Mosad