Eye drops are partially protective for the eyes, but they also have side effects. The composition of eye drops mostly includes active ingredients, pharmaceutical ingredients and preservatives. If you want to use eye drops to relieve eyestrain, preservative-free artificial tears are a safe choice. The ingredients mainly include sodium vitrate, carboxymethyl cellulose, and polyvinyl alcohol, which can moisturize the eye surface and have a mild effect of repairing eye surface damage. Even preservative-free artificial tears should not be abused as well as used for a long period of time, as they will dilute the beneficial components of the tears and destroy the physiological barrier and defense function of the tears. Long-term improper use of eye drops can injure the eyes. Preservatives contained in eye drops can irritate the eye surface, leading to keratitis, corneal ulcers, allergies and so on. Although eye drops have a therapeutic effect, but also produce adverse reactions, such as hormone eye drops can be used to treat eye infections, but can also cause elevated intraocular pressure, damage to vision; antibiotic eye drops long-term use will cause drug-resistant strains of bacteria to produce, so that the eyes of the decline in resistance, more susceptible to infection. Eye drops should be targeted medication to maximize the protective effect, and under the guidance of a doctor, not self-medication. If the eye condition does not improve, you need to consult a doctor.