Many parts of the human body are home to countless collections of microbes which include bacteria, fungi, and viruses. All of these are vital for keeping the human body healthy. The eyeballs also play host to a unique menagerie of microbes, which are known as eye microbiome.

The important factor for these types of microbiome that can be found in eyeballs is to keep it in perfect balance. Having too many or too few of certain types of the microbiome may cause eye diseases.

In a recent study, scientists are on a quest to discover the microbial factors that can be exploited to create innovative therapies for different eye disorders. This would include solutions for dry eye diseases, Sjogren's syndrome, and scarring in the cornea. The recent study has also revealed that bacteria live on the surface of the eyes and stimulate productive immunity.

A future goal is to make it possible to engineer bacteria which can treat eye diseases in humans.

For the past 10 years, scientists have believed that healthy eyes lack organized microbiome structure. Some scientists are banking on studies showing evidence that certain bacteria from the air, hands, or eyelid margin could be present on the eye as well because of exposure. However, there are also some who believe that these microbiomes were simply killed or washed away.

It was a recent study that has presented evidence that the eye does have a "core" microbiome that seems to be dependent on the human body's age, location, ethnicity, use of contact lenses, and the state of the disease.

According to the study, the "core" microbiome is limited to four genera of bacteria. This would include Streptococci, Propionibacteria, Diphtheroids, and Staphylococci.

In addition, the new study also included the torque teno virus, which is implicated in some intraocular diseases. The said bacteria also counts as a member of the core microbiome as it is present in the eye surface of over 65% of healthy individuals that were tested for the study.

The importance of the study is its implication where doctors should always think more deeply about the risks and benefits of the microbiome present in the eyes when prescribing antibiotics. Experts say that some antibiotics may kill the bacteria that are providing the eye with benefits.

A survey has revealed that antibiotics were used to treat 60% of acute conjunctivitis cases, more commonly known as pinkeye. However, experts pointed out that viral infections are the most likely causes of pinkeye, which are not actually treatable with antibiotics. Experts added that there are cases caused by bacteria which are often resolved within 7 to 10 days without the need for intervention. The scientific community wishes to put up a reminder that excessive or inappropriate antibiotic use could disrupt the body's natural microbiome which could lead to autoimmunity, infection, or in some cases, cancer.