Eye drops, available both over-the-counter and by prescription, are used to temporarily alleviate irritation, dryness, or redness. Many people believe that using these solutions more often than directed provides extra comfort. However, the overuse of eye drops, even artificial tears, is a common misuse that can lead to counterintuitive and sometimes serious negative effects on the ocular surface and overall health.
Understanding Different Types of Drops and Overuse
Overuse is defined as applying drops more frequently or for a period longer than recommended by the label or physician. Eye drops fall into several categories, and the risks of overuse vary significantly. Over-the-counter (OTC) redness relievers contain vasoconstrictors, which constrict blood vessels to temporarily whiten the eye. Lubricating drops, or artificial tears, treat dryness and are categorized by whether they contain preservatives, such as benzalkonium chloride (BAK), or are preservative-free. Prescription drops, such as those for glaucoma or inflammation, carry distinct risks related to their active pharmaceutical ingredient.
Immediate Local Effects and Dependency
Frequent and prolonged use of certain drops can paradoxically worsen the symptoms they are meant to treat, initiating a cycle of dependency. This effect is most notable with OTC redness-relieving drops containing vasoconstrictors. When these drops are used too often, the eye develops tolerance (tachyphylaxis), requiring more of the drug to keep vessels constricted. As the drug wears off, the blood vessels rebound and dilate more than before. This leads to “rebound redness,” forcing the user to apply drops even more frequently for relief.
Frequent application of preserved lubricating drops can cause irritation due to the preservative itself. Benzalkonium chloride (BAK) is a common preservative known to be cytotoxic, meaning it is toxic to the cells on the eye’s surface. When drops containing BAK are applied several times daily, the chemical can disrupt the natural tear film and damage the delicate surface layer of the cornea and conjunctiva. This toxicity results in increased dryness, irritation, and inflammation, prompting the user to apply more drops and compounding the problem.
Serious Long-Term and Systemic Complications
Chronic irritation from preservatives can lead to serious, long-term structural damage. Excessive exposure to BAK is associated with the loss of goblet cells, which produce the protective mucus layer of the tear film. This damage destabilizes the tear film and contributes to a chronic form of dry eye syndrome resistant to standard treatment. Overusing any drop to mask redness or discomfort can also delay the diagnosis of a serious underlying condition. Persistent eye redness can be a symptom of infection, severe allergy, or acute angle-closure glaucoma, and masking it prevents seeking necessary professional care.
When eye drops are overused, or applied incorrectly, a larger quantity of medication can drain through the tear ducts into the nasal passages. From there, active ingredients are absorbed into the bloodstream, leading to systemic side effects. This is a concern with prescription medications, such as beta-blocker drops used for glaucoma, which can slow the heart rate and lower blood pressure, posing a risk to individuals with cardiac conditions. Similarly, overuse of corticosteroid drops can lead to serious internal eye problems, including cataracts or a dangerous elevation of intraocular pressure.
Safe Usage and When to Seek Help
To minimize the risks of overuse, practice proper application techniques. Always wash your hands before handling the bottle and avoid touching the dropper tip to the eye or any other surface to prevent contamination. After instilling one drop, gently close the eye and press a finger over the inner corner of the eyelid for one to two minutes. This technique, known as punctual occlusion, blocks the tear duct opening. This significantly reduces the amount of medication absorbed into the body while maximizing the drug’s effect in the eye.
If you need to use lubricating drops more than four to six times a day, switching to a preservative-free formulation is advisable to prevent ocular surface damage. Preservative-free drops are typically packaged in single-use vials to maintain sterility. If you are using any type of eye drop and your symptoms persist, worsen, or if you develop new issues like pain, discharge, or changes in vision after 48 to 72 hours, discontinue use and consult an eye care professional immediately.