Question: What is Dry Eye Disease?
Dr. Rosenblatt: In reality, dry eye is an old name for a very common problem. The new name is ocular surface disease. It is a very common disease. Anywhere between 10-60 million people are afflicted with it in the United States. In people suffering from dry eye, their natural tear is not properly and healthily bathing their eye. The result of which can be symptoms of discomfort, stinging, burning, sandy gritty feeling, and fluctuating vision throughout the day (part of the day they see clearly other parts blurry).
Question: Why did they change the name from Dry Eye Disease to Ocular Surface Disease?
Dr. Rosenblatt: We are seeing it's not just a tearing issue per se, but patients have problems with the surface of the eye as well. We added the word disease because we wanted the public to think more seriously about this condition. We wanted to move away from the term "dry eye" because patients would come in and have a tissue constantly in their hands to wipe their eyes due to excessive tearing and so when we say to them that they have dry eye, it doesn't make sense to them.
Question: What causes ocular surface disease/dry eye?
Dr. Rosenblatt: The causes of dry eye are varied. In most cases we see that it's a chronic inflammatory disease. This means that it won't go away. We look at it nowadays as any other chronic diseases, like high blood pressure or diabetes.
The inflammation is within the tear gland. There are different types of tear glands which produce parts of the components of the tears. The most common are the Meibomian glands. Our tears are made up of mucus, oil and water. It takes the proper amount of each of those components to have a good quality tear that does its job.
We have two types of tears. We have the everyday, what I like to call the "sprinkler system" tears which are low-grade and constantly on. This is the tear that we are talking about that is being affected by the clogged glands and inflammation.
The other type of tear we have is reflexive tearing. This is the fire hydrant of tears. The problem with the fire hydrant of tears is it is not the same quality of tear. The volume is only increased because the water component was increased.
If someone has dry hands and washes them in tap water, immediately under the water they look great, but when they dry again, they will be dryer than they were before you put them in the water. This is because the hands, or in our case the tear is missing the additional moisture component of the oil and mucus.
The Meibomian glands tend to be the number one source of inflammation. They produce the lipid component of the tears, which helps the tear spread evenly across the eye, and helps coat the outer layer of the tear whereas the tears don't evaporate as quickly. So, without proper lipid content we get a tear that doesn't spread well and evaporates too fast, leaving dry eyes.
Question: Are some people or demographics more prone to ocular surface disease/dry eye than others?
Dr. Rosenblatt: Sure. Women are the number one group suffering from ocular surface disease. As women age and become post-menopausal their eyes tend to get more dry. People taking medication for hypertension are also more susceptible to dry eyes. People who wear contact lenses are also more susceptible to dry eye.
One of the things we are seeing today is younger people, including many children, with dry eye. This seems to us to be environmental, due to the extensive amount of time on electronic devices and computers. We see that the more people are looking at these devices, they don't blink as often and the eyes dry out. You see, blinking is a pumping action. When we blink we help pump those glands. Therefore, without the normal pumping the glands get clogged. If they clog and are untreated, later in life the glands will even die off.
Question: How do you diagnose ocular surface disease/dry eye?
Dr. Rosenblatt: When someone comes in with the above symptoms, we look at, using various techniques, certain biologic dyes which we have in particular. The tears are clear, so in order to see them we have to change their color temporarily.
There are technologies available to image those glands and see the their condition and how significant the problem is, and how clogged are: can we express them with some gentle pressure, what's coming out of them when we do express them if anything.
Then we look at the tears: in terms of the volume of the tears, how quickly they evaporate which is called the break up time of the tears, and the dye we used will also allow us to look at the surface of the eye and where there are breaks in the surface. Again, think of dry hands, and you see the flaky skin, that's sort of what your eye does too.
Our eye has an epithelial layer that we shed all the time, but when there is dryness present, we can see areas which are broken, and that's where the dye shows up. Another dye we use that only shows up where there is cell death. This is an indication of a long-standing problem.