Plain saline eye drops are available over the counter and can be used to moisten dry eyes or to wash irritants or small particles from the eyes. Medications, such as antihistamines, drugs to control intraocular eye pressure, pain relievers, steroids, and antibiotics can also be added to a saline-based eye drop. These medications are used to treat allergic reactions, glaucoma, eye injuries, and infections. Eye drops are usually administered using a dropper bottle which can deliver one or two drops in each eye.
Over-the-counter eye drops that contain just saline are most often used to lubricate dry eyes associated with contact lens use, allergies, or eye strain and fatigue caused by overuse of the eyes. In each of these situations, eye drops help to re-wet the eye when it has difficulty producing enough lubrication. These drops relieve eye discomfort or improve vision. In situations where dry eye is severe, an additional lubricating agent may be added to the drops to increase the viscosity of the solution and help it cling to the eye and last longer.
Medications used in the eye are added to saline solutions for several reasons. The chemistry of saline-based eye drops can be matched closely to the aqueous environment of the eye so that delivery of the medication does not disrupt the balance of the eye and cause further damage or irritation. In addition, adding medications to saline drops allows manufacturers to easily control the concentration of the medication.
Some of the most common medications added to eye drops are antihistamines, topical pain relievers, steroids, and antibiotics. Antihistamines are added to eye drops to prevent the itchiness and irritation associated with allergies. Saline eye drops that contain a topical pain reliever are usually used to reduce the pain associated with an eye infection, abrasion, or burn. Steroids eye drops are used to reduce eye swelling associated with a bad allergic reaction, infection, or eye injury. Antibiotic eye drops are used to treat eye infections.
Glaucoma is a disease in which the intraocular pressure inside the eye increases, placing pressure on and potentially damaging the optic nerve which shunts visual information to the brain. There are several groups of drugs, such as beta receptor blockers, that are added to eye drops to help lower the intraocular pressure. Use of these types of eye drops can prevent the eye damage and the potential blindness that can result from glaucoma.
When administering saline eye drops, the patient should wash his hands and then shake the bottle to mix the contents. The lower eye lid should be gently extended with a finger and the appropriate number of drops placed directly in the eye without allowing the bottle to touch the eye. Once the drops are in the eye, the patient should close his eyes for a few minutes.