Crying involves the production of tears, a natural bodily response to emotions or physical irritations. Many individuals experience a burning or stinging sensation in their eyes during or after crying. This can be perplexing, as tears are typically associated with cleansing and protecting the eyes. Understanding the underlying biological and chemical processes clarifies why this temporary discomfort occurs.
The Purpose and Composition of Tears
Tears play a crucial role in maintaining eye health and function, serving as a protective and lubricating barrier for the ocular surface. They continuously moisten the eyes, preventing dryness and irritation, and form a smooth optical surface over the cornea, contributing to clear vision.
Tears contain various components that defend against foreign particles and microbial invaders. These include water, electrolytes such as sodium and potassium, and proteins like lysozyme and lactoferrin. Enzymes also possess antimicrobial properties, helping to wash away debris and fight potential infections.
The Chemical Reasons for the Burning Sensation
The burning sensation during crying is primarily due to chemical and physiological changes in the tear film and on the eye’s surface. A significant factor is the alteration in tear osmolarity, which refers to the concentration of salts and other solutes. During intense crying, the watery component of tears can evaporate quickly or be produced in excess, leading to a higher concentration of solutes, making the tears “too salty.” This osmotic imbalance can irritate delicate cells on the eye’s surface.
Changes in the pH balance of tears also contribute to discomfort. While tears normally maintain a slightly alkaline pH, fluctuations can occur. Deviations from this optimal pH can disrupt the ocular surface, leading to stinging or burning sensations.
The eye’s response to irritation can trigger a mild inflammatory response, contributing to discomfort. Additionally, excessive crying can disrupt the protective mucin layer that coats the eye. This disruption exposes sensitive nerve endings on the corneal surface, making the eye more vulnerable to irritation and enhancing the perception of burning.
Different Types of Tears and Their Characteristics
The eye produces three distinct types of tears, each with unique compositions and functions that can influence the burning sensation.
Basal Tears
Basal tears are continuously produced to lubricate the eyes and provide a constant protective layer. These tears primarily consist of water, electrolytes, and essential proteins for daily eye health.
Reflex Tears
Reflex tears are generated in response to irritants, such as dust, smoke, or onion compounds. Their primary role is to flush out foreign substances and contain a higher concentration of antibodies and enzymes. The elevated salt content in reflex tears, necessary for cleansing, can contribute to a temporary stinging or burning sensation.
Emotional Tears
Emotional tears are produced during strong emotional states like sadness, joy, or stress. These tears have a distinct chemical profile compared to basal or reflex tears, often containing higher levels of stress hormones and proteins. Their unique composition and often larger volume can lead to a more pronounced burning sensation due to increased irritants and extended contact time.
Addressing Persistent Eye Discomfort
A temporary burning sensation after crying is often a normal physiological response and typically resolves on its own. However, persistent or severe eye discomfort, redness, or pain following crying could indicate an underlying issue requiring medical attention. Conditions such as dry eye syndrome, involving insufficient or poor-quality tears, can exacerbate burning sensations.
If burning persists, or if you notice other concerning symptoms like blurry vision, discharge, extreme light sensitivity, or signs of infection, consult an eye care professional. For temporary relief, gently blinking can help redistribute the tear film. Applying a cool compress to closed eyelids may also soothe irritation. Over-the-counter artificial tears can provide additional lubrication and comfort, but avoid rubbing the eyes, as this can worsen irritation.