“Doctor, my eyes feel dry. They feel gritty, they burn, they get blurry. They’re irritated. Sometimes, they water.” Is this you or someone you know? These are not uncommon complaints heard in our office. These complaints are all part of Dry Eye Syndrome, but just because these symptoms are common, it doesn’t mean that we have to live with these issues. In fact, ignoring these symptoms can lead to serious eye disease.
Before we can understand Dry Eyes, we have to understand the role of normal tears. Normal tears have two main functions – they keep our corneal cells healthy and lubricated, and they form our primary optical surface so that we can see clearly and consistently. These tears come from glands located in the eyelids. Normal tears are different from Reflex tears. Reflex tears are the tears we get when our eyes become irritated, something gets in our eyes, or we cry for emotional reasons. These tears wash away the irritants, and this is why watery eyes may be the result of the irritation of dry eyes. They don’t stick to the eyes like normal tears do, so they don’t really solve the problem.
Why do we get dry eyes? Dry Eye sufferers have at least one, if not all four, of these problems:
- Tear film instability or hyperosmolarity.
- Biofilm formation
- Obstruction of meibomian glands.
The Meibomian glands are found in our eyelids and secrete thin oil into the tear film which floats to the top of the tears and keeps them from evaporating. It is thought that meibomian gland dysfunction may be responsible for as much as 90% of dry eye problems. For this reason, doctors are starting to refer to Dry Eye Syndrome as Eyelid Inflammation, or Blepharitis. Sometimes it is called Meibomian Gland Disease or MGD. When our meibomian glands are not working properly, instead of secreting thin oil, they become plugged with a thicker paste-like substance, which can lead to the glands dying altogether.
Well then, what causes meibomian glands to malfunction? One reason has been linked to our modern diet which contains an especially high ratio of Omega-6 fatty acids to Omega-3 fatty acids. Another reason goes to how we use our eyes today, specifically because of all the time we spend looking at computers, tablets, and smart phones. When we concentrate, whether using these devices or just reading, we don’t blink as much. Blinking causes meibomian glands to release some of their oil. Other causes include systemic conditions and inflammations such as arthritis, diabetes, rosacea and thyroid disease as well as medications we take such as antihistamines, antidepressants, and estrogens.
How do I know if I have dry eyes, eyelid disease, or how bad it is? If you are having any of the symptoms listed above: dryness, burning, grittiness, or other irritation, you should schedule an appointment with us or with your eye doctor. You should also schedule an appointment if you or someone else notices that your eyes or eyelids look red or have debris in your eyelashes. If you use any artificial tears, but find that you need to use them more than 2-3 times per day, this would also be a reason to schedule an appointment.
There are several tests that we use to determine how to treat your dry eye. These include:
- A standardized questionnaire like the Standard Patient Evaluation of Eye Dryness (SPEED) survey or the Ocular Surface Disease Index (OSDI)
- Tear sampling to determine salt concentration
- Tear sampling to determine the presence of inflammatory markers
- Microscopic examination to look at the general appearance of the eyes and eyelids
- Dyes to look for damaged and missing corneal and conjunctival cells
- Tear film break-up time following a blink
- Meibomian gland expression