Manatees' eyes offer glimpse at health

GAINESVILLE, FLA. - 7/26/05 - Researchers at the University of Florida (UF) studying the thick tear film of Florida manatees aim to prove whether the uncommonly thick tear aids in disease protection and believe it can reveal information about the animal's health.

Scientists contend that tear analysis in conjunction with standard tests might provide helpful information for evaluating the manatees' immune system and thus determining approaches for rescuing, treating and rehabilitating these large sea mammals.

A recent study analyzing the large amount of blood vessels present in the manatee's cornea provides the framework for this research. Don Samuelson, PhD, a professor of ophthalmology in the Marine Mammal Medicine program at UF's College of Veterinary Medicine, says blood vessels may move into the cornea to provide oxygen because the thick tear film prevents oxygen from reaching it.

Thick film provides the necessary protection that allows manatees to travel into waters that would otherwise be detrimental to their health, Samuelson says. Scientists are exploring connections between this protective film and the blood vessels in the cornea, which form in the early stages of development.

"With that in mind, we are examining the tears to see what they exactly consist of, particularly with regard to the anti-infectious component," Samuelson says. Eventually, this might be an opportunity to examine an individual manatee's state of health with regard to its immune system by analyzing their tears, he adds.