Many people experience tears unexpectedly emerging when they lie down. This common occurrence stems from several physiological mechanisms within the eye’s tear system. Understanding these processes can explain why your eyes might water when you recline, even without emotional triggers.
Understanding Your Tear System
The eye’s surface is constantly lubricated and protected by tears, part of the lacrimal apparatus. Tears are primarily produced by the lacrimal glands, located above the outer corner of each eye. These glands secrete a watery fluid containing salts and protective components.
As you blink, tears spread across the cornea, forming a protective tear film. This film consists of three layers: a mucin layer that helps tears adhere to the eye, a watery aqueous layer from the lacrimal glands, and an outer oily layer from meibomian glands along the eyelid margins. The oily layer prevents tears from evaporating too quickly and keeps them from spilling over the eyelids.
After lubricating the eye, tears drain through small openings called puncta in the inner corners of your eyelids. From the puncta, tears flow into tiny channels called canaliculi, leading to the lacrimal sac. The lacrimal sac then empties into the nasolacrimal duct (tear duct), which drains into the nasal cavity. This explains why crying can lead to a runny nose.
Why Tears Appear When You Lie Down
Tears can appear when you lie down for several reasons, often related to how gravity and other factors influence the tear system’s balance.
Gravity and Drainage
When upright, gravity assists in guiding tears towards the puncta for drainage. However, when lying horizontally, this gravitational assistance is reduced. Tears may pool on the eye’s surface or overflow more easily because the passive drainage mechanism is less effective.
Tear Duct Obstruction
Even a partial obstruction in the tear drainage system, such as a narrowed nasolacrimal duct, can become more noticeable when lying down. While minor blockages might not cause overflow when upright, the horizontal position can make these impediments more apparent, leading to tear buildup and overflow.
Dry Eye Syndrome
Paradoxical tearing is a symptom of dry eye syndrome, where irritated eyes reflexively produce excessive tears as a protective response. When lying down, blinking may occur less frequently, which can exacerbate dry eye symptoms and trigger reflex tearing. Additionally, the sleeping environment, such as dry air from a fan or air conditioning, can irritate already dry eyes, leading to increased tear production.
Environmental Irritants
Environmental irritants in the sleeping area can also contribute to tearing. Allergens like dust mites, pet dander, or even certain bedding materials can irritate the eyes, prompting them to produce more tears to flush out the irritants.
Eyelid Position
The position of your eyelids can change when you lie down. Eyelid laxity or pressure from a pillow can cause the eyelids to open slightly, exposing the eye surface to air and increasing evaporation. This exposure can lead to irritation and reflex tearing as the eye attempts to re-lubricate itself.
When to Consult a Doctor
While occasional tearing when lying down is benign, certain symptoms warrant a consultation with an eye care professional. Seek medical attention if excessive tearing is accompanied by vision changes, such as blurriness or loss of clarity. Persistent pain or discomfort around the eyes also indicates a need for evaluation.
Other symptoms include persistent redness, a feeling that something is in your eye, or discharge or crusting around the eyelids. Swelling near the inside corner of the eye or unexplained bruising around the eye also prompts a medical visit. If tearing is constant, significantly impacts daily life, or if home remedies do not provide relief, consult a healthcare professional to rule out underlying medical conditions like infection or a blocked tear duct.
Practical Tips for Comfort
Several steps can help alleviate tearing when you lie down, addressing common contributing factors. If dry eyes are suspected, using over-the-counter artificial tears (preservative-free varieties) before bed can lubricate the eyes and reduce reflex tearing. Ensuring a clean sleeping environment by regularly washing bedding and reducing dust minimizes exposure to common allergens that irritate the eyes.
Using a humidifier in your bedroom adds moisture to the air, helpful if you live in a dry climate or use heating/air conditioning that dries out the air. Positioning yourself to avoid direct airflow from fans or air conditioning vents onto your face also prevents eye irritation and excessive tearing. Taking breaks from screens before bedtime and ensuring all makeup is removed can reduce eye strain and irritation that might contribute to watering.