Important differences exist between the various classes of over-the-counter eye drops. Physicians play a vital role in explaining these differences, as well as their potential implications in the treatment of the symptoms of dry eye and other conditions, to patients. Educating patients about the available formulations not only may expedite the relief of their symptoms but also may save them time and money.
Although the majority of treatments for dry eye are OTC artificial tears, economic conscientiousness almost certainly is present in OTC markets as well. Even in a healthier economic climate, a person experiencing burning, stinging, or red eyes might first take a trip to the pharmacy and choose one of the plethora of eye drops on the drug store's shelves.2
Two key classes exist
As to the differences between two key classes of OTC eye drops-vasoconstrictors and ocular lubricants-patients experiencing dry eye may not be aware of potential implications of different formulations. The aforementioned research also demonstrated that two-thirds of women surveyed apparently were unaware of the differences between artificial tears and vasoconstrictors.3 This statistic is alarming because vasoconstrictors, when applied topically to the eye, constrict blood vessels and are intended to address short-term redness, such as that caused by swimming in a chlorinated pool.
These agents do not benefit ocular surface lubrication. In fact, the FDA Ophthalmic Drug Products for Over-the-Counter Human Use monograph explicitly states concern for "the overuse or unnecessary use of OTC ophthalmic vasoconstrictor ingredients."5
The document goes on to explain risks such as delay in treatment of underlying conditions causing redness and potential side effects including "excessive cell loss, prolonged constriction of conjunctival blood vessels and subsequent dilation of the blood vessels" as well as ocular stinging and burning.
The monograph allows for the following vasoconstrictors in given percents in OTC ophthalmic formulations: ephedrine hydrochloride (0.123%), naphazoline hydrochloride (0.01 to 0.03%), phenylephrine hydrochloride (0.08 to 0.2%), and tetrahydrozoline hydrochloride (0.01 to 0.05%), and stipulates several warnings necessary for inclusion in the packaging.
For patients presenting with complaints of symptoms such as ocular dryness, burning, stinging, photophobia, or grittiness, a series of clinical tests to identify dry eye should be performed. Differential diagnosis of other common redness-causing conditions, such as bacterial conjunctivitis or allergic conjunctivitis, also is necessary to administer proper treatment.
The verbal description that the patient uses, for example, could include complaints of "itchy eyes," which could suggest allergic conjunctivitis. If the patient instead uses the phrase to describe a desire to rub his or her eyes, then the symptom actually might be occurring in response to dryness and thus would indicate an attempt to relieve the discomfort. Delicate questioning as to whether the patient's itchiness is akin to that of an insect bite could help clarify this distinction.