How Do Tears Work?

When you blink, a film of tears spreads over the eye. This keeps the eye’s surface smooth and clear. The tear film is important for good vision.

The tear film is made of three layers:

• An oily layer
• A watery layer
• A mucus layer

Each layer of the tear film serves a purpose.

The oily layer is on the outside of the tear film. It makes the tear surface smooth and keeps tears from drying up too quickly. This layer is made in the eye’s meibomian glands.

The watery layer is in the middle of the tear film. It makes up most of what we see as tears. This layer cleans the eye, washing away particles that do not belong in the eye. This layer comes from the lacrimal glands in the eyelids.

The mucus layer is the inner layer of the tear film. This helps spread the watery layer over the eye’s surface, keeping it moist. Without mucus, tears would not stick to the eye. Mucus is made in the conjunctiva. This is the clear tissue covering the white of your eye and inside your eyelids.

Normally, our eyes constantly make tears to stay moist. If our eyes are irritated or we cry, our eyes make a lot of tears. But sometimes the eyes don’t make enough tears, or something affects one or more layers of the tear film. In those cases, we end up with dry eyes.

Dry eye symptoms:

• You feel like your eyes are stinging and burning.
• There is a scratchy or gritty feeling like something is in your eye.
• There are strings of mucus in or around your eyes.
• Your eyes are red or irritated. This is especially true when you are in the wind or near cigarette smoke.
• It is painful to wear contact lenses.
• You have lots of tears in your eyes. Having a lot of tears in your eyes with “dry eye” might sound odd. But your eyes make more tears when they are irritated by dry eyes.

Dry eye causes:

• People tend to make fewer tears as they get older due to hormonal changes. Both men and women can get dry eyes. However, it is more common in women—especially those who have gone through menopause.
• Blepharitis (when eyelids are swollen or red).
• Entropion (when eyelids turn in); ectropion (eyelids turn outward).
• Being in smoke, wind, or a very dry climate.
• Looking at a computer screen for a long time, reading, and other activities that reduce blinking.
• Using contact lenses for a long time.
• Diseases such as diabetes, rheumatoid arthritis, thyroid disease, Parkinson’s, and rosacea.
• Taking certain medicines, such as:
  • Diuretics (water pills) for high blood pressure.
  • Beta-blockers, for heart problems or high blood pressure
  • Allergy and cold medicines (antihistamines)
  • Sleeping pills
  • Anxiety and antidepressant medicines
  • Heartburn medicines

It is advisable to tell your ophthalmologist about all the prescription and non-prescription medicines you take.

Dry Eye Diagnosis and Treatment:

It usually begins with a detailed eye exam. The eyelids, the surface of the eyes, as well as the blink rate is checked.

There are many different tests that help diagnose dry eye such as Ocular surface staining, TBUT, Schirmer’s, Meniscometry that measures the quality or the thickness of tears, how quickly you produce tears and how effectively they wet the eyes.

How Is Dry Eye Treated?

• Adding Tears: Artificial tear eye drops that are like your own tears. You can use artificial tears as often as you need to. If you use artificial tears more than six times a day or are allergic to preservatives, you should use preservative-free tears. This is because if the tears with preservatives are used a lot, these chemicals may start to irritate your eyes.
• Saving Tears: You can have punctal plugs (tiny silicone or gel plugs) inserted into your tear ducts to block them, which keeps your natural tears in your eyes for a longer duration. You can later have these plugs removed as required. Alternatively, punctal cautery offers a permanent solution.
• Treating Dry Eye Culprits: You can treat eyelid problems such as MGD (Meibomian gland dysfunction) and Blepharitis by applying warm compresses to the eyes, massaging the eyelids, using eyelid cleaners like baby shampoo, and applying nighttime ointments to reduce inflammation. Doctors often prescribe steroid eye drops to help break the cycle of inflammation.

As a dietary supplement (pill or tablet), you can add Omega-3 fatty acids. These naturally occur in oily fish (like salmon, sardines, tuna, trout, and anchovies) as well as in flaxseeds.

Dry Eye Prevention Tips:

• • Try not to use a hair dryer, if possible. Avoid using facial cosmetics and hair dye as the vapors from them can further irritate the eyes.
  • Stay away from very warm rooms. In the winter, add moisture to the air with a humidifier. Or put a pan of water near your heater or radiator.
  • Protect your eyes from drying wind by wearing wrap-around glasses outside.
  • 20-20-20 rule – For every hour of reading or watching TV, take a break and look away from the screen (at a distance of at least 20 feet) for at least 20 seconds and blink frequently (20 times/minute).
  • Avoid cigarette smoke and alcohol

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Written and Verified by:

DR. ARUN SINGHVI

MBBS, MD (AIIMS, NEW DELHI) & FRCS (A) PHACO, FEMTO, CORNEA & REFRACTIVE (Q-LASIK, ICL & BIOPTICS)

MEET THE EXPERT