The term “mRNA” became familiar to many people during the COVID-19 pandemic. Because it was part of the technology behind the Pfizer-BioNTech and Moderna vaccines, some people understandably came to think of mRNA as something artificial or potentially dangerous. The reality is quite different. Messenger RNA, or mRNA, is a normal and essential part of life. It is present throughout our bodies and has been doing its job in our cells since long before mRNA vaccines were developed.
Think of DNA as the master set of instructions stored safely inside the nucleus of a cell. DNA contains the information needed to make proteins, which perform countless jobs throughout the body. When a cell needs to make a particular protein, it creates a temporary copy of the appropriate instructions in the form of mRNA.
The mRNA then travels outside the nucleus to a cellular structure called a ribosome. The ribosome reads the mRNA and uses its instructions to assemble the appropriate protein. Once its job is finished, the mRNA is broken down and recycled by the cell. This is a normal process occurring continuously in our bodies.
This same natural process is what scientists learned to use in mRNA vaccines. Rather than putting a weakened or inactivated virus into the body, an mRNA vaccine temporarily provides cells with instructions for making a harmless piece of a virus. The immune system recognizes that protein and learns how to respond to it. The mRNA is then rapidly broken down. It does not enter the cell’s nucleus and does not alter a person’s DNA.
mRNA vaccines have been studied extensively and have demonstrated a strong safety record. Like any medical treatment, vaccines can produce side effects, but most are mild and temporary. The safety of vaccines also continues to be monitored after they are approved.
So what does all of this have to do with your eyes?
Quite a lot. The cells of the eye depend on mRNA every day. Cells in the retina, cornea, lens, optic nerve and other eye tissues constantly use mRNA to produce the proteins necessary for normal vision and healthy tissue.
Scientists are now exploring whether this same technology can be used to treat eye diseases. Researchers are investigating mRNA-based treatments for conditions such as age-related macular degeneration, inherited retinal diseases, diabetic retinopathy and other disorders involving the retina. One potential advantage is that mRNA can provide cells with temporary instructions to produce a needed protein without permanently changing the cell’s DNA.
For example, some inherited retinal diseases occur because a genetic mutation prevents cells from producing an important protein. Researchers are studying whether mRNA could temporarily provide the instructions needed to produce that protein. Other research is examining whether mRNA could influence the immune system, blood vessels or other cellular processes involved in diseases such as macular degeneration and diabetic retinopathy.
These approaches remain an area of active research, and mRNA treatments are not yet established therapies for most of these eye diseases. However, the technology represents an exciting area of future ophthalmic medicine.
The important point is that mRNA is not a mysterious substance introduced into our bodies by modern medicine. It is one of the fundamental mechanisms by which our cells function. Modern medicine has simply learned how to take advantage of a process that biology has been using all along—including in the cells of our eyes.