ABMS board certified ophthalmologist Grace Zhang, MD, answers pressing questions about the role tears play in eye health.

There are three main types of tears:

  • basal
  • reflex
  • emotional

Each unique type of tear serves a different purpose. But all three types of tears work together to play an essential role in maintaining eye health and responding to the various environmental and emotional stimuli you might experience on a daily basis.

What role do basal tears play?

Basal tears are the tears that our lacrimal glands produce to keep the eyes moist and lubricated. They help maintain a smooth surface on the cornea and protect against irritants. They prevent the eye from drying out and provide a baseline level of lubrication for normal eye function.

What role do reflex tears play?

Reflex tears are formed when your eyes need to wash away harmful irritants, such as smoke, foreign bodies, or vapor from cutting onions. Your eyes release reflex tears in larger amounts than basal tears. They may also contain extra antibodies to help fight bacteria.

What role do emotional tears play?

Emotional tears are produced in response to joy, sadness, fear, and other emotional states. Emotional tears can overflow and roll down the sides of our cheeks. They’re unique to humans.

Emotional tears have a similar chemical makeup as basal tears, but they contain more stress hormones and pain relievers not found in basal or reflex tears, such as:

  • prolactin, or adrenocorticotropic hormone (indicates high stress levels)
  • potassium (a type of electrolyte)
  • manganese (a mood-regulating hormone)

Our tears are produced by the lacrimal glands that are above our eyes.

Tears are made of:

  • water
  • lipids
  • enzymes
  • electrolytes

The different types of tears have different compositions, as outlined above, but all have three layers:

  • Inner mucus layer: the glue that keeps the tear on the cornea, or the outer layer of the eye
  • Middle water layer: the thickest layer providing hydration and repels bacteria
  • Outer lipid (oil) layer: keeps the surface of the eye smooth and prevents tears from evaporating

Tears are essential for good vision and maintaining the health of our eyes.

The normal ocular surface is covered by a layer of tear film. This tear film is the initial refractive surface of the eye, which bends light into focus. The maintenance of a stable, healthy tear film is of paramount importance to vision.

Imagine a clear lake in which you can see to the bottom. The view will be poor if there is much less water or if there is a lot of debris in the lake.

You cannot “run out” of tears. The tear production process is ongoing. The eyes constantly produce basal tears for lubrication, and additional tears are generated in response to emotions or irritants.

However, in certain situations, there could be significantly decreased basal tear production. Aging is the most common cause. Other examples are going through menopause and living with certain medical conditions such as Sjögren disease.

Tear production decreases as part of the aging process. Dry eye affects an estimated 6.8% of adults, and the risk of developing dry eye increases with age.

When you do not produce enough tears, the tear film becomes unstable with the loss of water, and a progressive deterioration of the ocular surface ensues.

Talk with a doctor if you’re experiencing dry eye.

Together, you can discuss if you’re on any medications that can exacerbate dry eyes, such as antihistamines, or nonprescription cold decongestants, such as pseudoephedrine.

They can also help determine if you may have any systemic diseases associated with dry eyes, such as autoimmune disorders like Sjögren disease, Bell’s palsy, or multiple sclerosis.

For mild dry eyes, a doctor may recommend options such as:

  • using artificial tears with preservatives up to four times daily
  • lubricating ointment at bedtime
  • applying warm compresses
  • massaging the eyelid

For moderate dry eyes, a doctor may recommend the above remedies, as well as using punctal plugs that occlude the tear duct on your lower eyelids.

For severe dry eyes, in addition to the above strategies, they may also recommend prescription dry eye medication, such as cyclosporine, that helps you produce your own tears.

Using a humidifier or wearing moisture shields over the eyes can also help create a moist environment.

Dr. Grace Zhang is an ABMS board certified ophthalmologist with almost 2 decades of experience. She practices in Santa Rosa, California. Dr. Zhang finds ophthalmology rewarding because she can practice medicine, perform microsurgery, and remain aware of the constantly evolving technology in this field.