Is it possible to cry with one eye? The surprising answer behind unilateral tears

September 30, 2025 •

5 min read

According to the American Academy of Ophthalmology, humans produce three types of tears: basal, reflex, and emotional. While emotional crying is typically a bilateral, symmetrical response, it is indeed possible to cry with one eye due to a variety of physiological reasons. This phenomenon, known as unilateral epiphora, can result from issues affecting the delicate tear production and drainage system on one side of the face.

Quick Summary

It is physiologically possible to produce tears from only one eye due to differences in tear drainage, irritation, or an obstructed lacrimal duct. This can be caused by allergies, physical trauma, or neurological conditions affecting one side of the face. The asymmetry often relates to specific medical conditions rather than emotional control.

Key Points

Asymmetrical Tears: It is physically possible and normal to produce tears from only one eye, especially when the cause is a physical irritant rather than a strong emotion.
Blocked Tear Duct: One of the most common reasons for consistent unilateral tearing is a blocked or narrowed tear duct on that side, preventing tears from draining properly.
Irritation is Key: Reflex tears, produced to flush out irritants like dust or onion fumes, can be triggered in just one eye if that eye is more exposed to the irritant.
Not an Emotional Trait: Unilateral emotional crying is rare; when it occurs, it may indicate a neurological or anatomical asymmetry rather than a person’s ability to control their emotions.
Medical Evaluation Recommended: Persistent, one-sided watery eyes (epiphora) should be evaluated by an eye doctor to rule out underlying infections, blockages, or other medical issues.
Dry Eye Paradox: Ironically, dry eye syndrome can cause one or both eyes to water excessively as the body attempts to compensate for the dryness.

Can a person truly cry with a single eye?

Yes, it is entirely possible to cry with one eye. While emotional crying, which is controlled by the limbic system of the brain, usually triggers the lacrimal glands above both eyes, a number of physiological factors can lead to tears flowing from only one eye. The phenomenon is often related to an asymmetry in the tear production or drainage systems. While actors like Leonardo DiCaprio may be able to conjure a single tear for dramatic effect, this is typically a learned skill involving emotional recall, while persistent unilateral crying is usually a sign of a physical issue.

The three types of tears

To understand why crying with one eye occurs, it helps to know the different types of tears your body produces:

Basal Tears: These are constant, lubricating tears that keep the surface of your eyes moist, nourished, and protected from debris. They contain antimicrobial proteins and are crucial for vision and eye health.
Reflex Tears: These tears are produced in large volumes to wash away irritants like dust, smoke, onion fumes, or foreign objects. They contain antibodies to fight bacteria and can easily be triggered in just one eye if only that eye is irritated.
Emotional Tears: Triggered by strong emotions such as sadness, joy, or grief, these tears are chemically distinct. They contain higher levels of stress hormones and proteins, which some scientists believe helps the body release stress and return to a more balanced state.

The anatomy of tears

Each eye has its own tear production and drainage system, which is why crying with one eye is physically possible. The lacrimal gland, located above the outer corner of each eye, produces tears. The tears then flow across the eye and drain through small openings called puncta, located in the inner corners of the eyelids. From there, the tears travel through tiny canals into the nasolacrimal duct and eventually drain into the nasal cavity. Any blockage, irritation, or impairment in this system on one side of the face can result in unilateral tearing.

Common causes of unilateral tearing

Persistent unilateral tearing, known as epiphora, can be caused by a range of underlying issues. It's important to differentiate between temporary instances of one-sided watering and chronic conditions that require medical attention.

Blocked Tear Duct (Nasolacrimal Duct Obstruction): This is a very common cause of one-sided watering eyes, especially in infants. If the duct is blocked, tears cannot drain normally and will overflow onto the cheek, even during normal tear production. In adults, blockages can occur due to age-related narrowing, inflammation, or trauma.
Eye Irritation: A foreign body like a speck of dust, an ingrown eyelash, or an allergic reaction can cause a reflex tearing response in only one eye. This is a natural defense mechanism to flush out the irritant.
Dry Eye with Reflex Tearing: Paradoxically, dry eye syndrome can cause excessive tearing. When the eye's surface is dry, it can trigger the lacrimal gland to produce a flood of reflex tears. If this condition is more severe in one eye, you may experience unilateral tearing.
Conjunctivitis: Also known as pink eye, this inflammation of the conjunctiva can affect one or both eyes and cause redness, irritation, and increased tearing.
Infections and Inflammation: Conditions like dacryocystitis (inflammation of the tear sac) or herpes eye infections can cause symptoms, including excessive tearing, in only one eye.
Neurological Issues: In rare cases, aberrant facial nerve regeneration (crocodile tears syndrome) can cause tearing in one or both eyes while eating. Conditions like Bell's palsy can also affect tear production.
Structural Abnormalities: Lumps, cysts, or tumors around the eyelid or tear duct can obstruct drainage and cause unilateral tearing. Trauma can also cause scarring or damage to the lacrimal drainage system.

Comparison of common unilateral tearing causes


Cause	Mechanism	Key Symptoms	What to Look For	Medical Evaluation
Blocked Tear Duct	Obstruction of the nasolacrimal duct, preventing drainage.	Persistent watery eye, possible discharge, swelling.	Tears frequently spill onto the cheek, especially when not crying emotionally.	Recommended. An eye doctor can perform a sac wash-out or probing.
Reflex Irritation	Response to a foreign body, allergens, or irritants in one eye.	Sudden watering, temporary redness, foreign body sensation.	Symptoms appear abruptly and typically resolve once the irritant is removed.	As needed. If irritation persists or object is lodged, see a doctor.
Dry Eye Syndrome	Eye's surface is dry, triggering overproduction of tears as a compensatory mechanism.	Burning, grittiness, blurriness, and watery eyes.	Symptoms are chronic and accompanied by dry eye signs; tearing may be worse in cold or windy air.	Recommended. An eye doctor can diagnose and recommend treatments like artificial tears.
Infection/Inflammation	Infection or inflammation affects the tear sac or conjunctiva.	Tearing with redness, pain, discharge, or crusting.	Accompanied by other signs of infection; symptoms typically do not resolve on their own.	Recommended. A doctor can diagnose and prescribe appropriate treatment.

When should you see a doctor?

If you experience persistent one-sided tearing, or if it is accompanied by other symptoms, it is advisable to consult an eye care professional. While occasional unilateral watering due to irritation is normal, a consistent issue could indicate an underlying medical condition. You should see a doctor if you notice persistent tearing, redness, pain, or any changes to your vision in one eye. A comprehensive evaluation can help identify the root cause and ensure you receive the correct treatment.

Conclusion

So, is it possible to cry with one eye? Yes, and the reason is often more physiological than emotional. While emotional tears are typically produced bilaterally, one-sided tearing, or epiphora, can result from an asymmetry in the tear drainage system. The causes range from simple irritants and allergies to more complex medical conditions like blocked tear ducts, infections, or dry eye syndrome. If you're experiencing chronic tearing from a single eye, consulting an ophthalmologist is the best course of action to diagnose the problem and find a suitable solution. For more information on different types of tears, consult the American Academy of Ophthalmology's website.

Frequently Asked Questions

Yes, it is normal for one eye to water more in cold, windy, or dry conditions. This can happen if one eye is more exposed to the elements or if there are slight differences in the tear drainage systems between your eyes.

Yes, allergies can cause irritation and swelling in one eye, triggering it to produce more reflex tears to flush out the allergens. This can result in unilateral tearing if the allergen exposure or reaction is concentrated in one eye.

Infants often have a congenital blocked tear duct, which is a common and usually temporary issue that can cause one eye to water excessively. While it often resolves on its own, it's wise to consult a pediatrician or ophthalmologist for advice.

While difficult to do intentionally for emotional tears, some actors and individuals can use tricks, like rubbing the inner corner of one eye to induce a physical reflex tear. However, this is different from genuine emotional crying.

Yes, a dry eye can cause compensatory reflex tearing. If the dry eye condition affects one eye more severely than the other, it can cause unilateral watering. It may sound counterintuitive, but it is a common symptom.

Yes, if a foreign object like dust or an eyelash enters your eye, it will trigger a reflex tear response to flush it out. Since the irritant is only in one eye, the tearing will be unilateral.

You should see an eye doctor if you experience persistent one-sided tearing, especially if it's accompanied by pain, redness, swelling, or blurred vision. A professional can diagnose the underlying issue and recommend treatment.