When your natural tears are unable to provide enough moisture or lubrication to your eyes, artificial tears (lubricating eye drops) can help. However, not all artificial tears are the same. They can have different active ingredients, preservatives, and packaging. For example, they can be in the form of liquid, gels, ointments, or sprays.
What are preservatives?
Preservatives are chemicals that are sometimes used to prevent contamination or decomposition of a medicine or liquid. When an eye drop medicine is exposed to oxygen or a nonsterile surface it becomes at risk for contamination or decomposition. Some artificial tears contain preservatives to prevent this. Certain preservatives, such as benzalkonium chloride (BAK)can harm the surface of your eyes. Using more than 4 drops a day of artificial tears containing BAK increases the likelihood of side effects caused by BAK.
Some tear substitutes contain preservatives that can damage the surface of your eye, such as BAK. This damage prevents the artificial tears from keeping the tear film in place.
Are all preservatives the same?
No. There are many different types of preservatives and some are safer than others.
Benefits of preservative-free tears
There are artificial tear products that do not use preservatives and are packaged in single-use containers. Products such as Oasis TEARS and Oasis TEARS PLUS remain sterile and unexposed to oxygen. Studies have shown that preservative-free eye drops are safe to use in patients, even when frequently used.