Eye drops can be used to deliver a variety of medications, from “artificial tears” to antibiotics. The major allergy drug categories delivered through eye drops include:

• Antihistamines. Medications that attach to histamine receptors, preventing the chemical histamine from triggering symptoms of an allergic reaction. This helps keep the blood vessels in the eye from swelling. They also relieve eye itchiness and redness. Eyes drops have a quicker onset and cause less drying of the eye than oral antihistamines. Antihistamines are available in both over-the-counter and prescription forms. Examples include:
  
  
• • Azelastine (Optivar)
  • Emedastine (Emadine)
  • Ketotifen (Zaditor)
  • Levocabastine hydrochloride (Livostin)
  • Olopatadine (Patanol)
  • Pheniramine (Opcon-A)
    
    
  
  
  
  
• Decongestants. Shrink blood vessels in the eyes that are swollen because of exposure to an allergen. This decreases eye redness, reduces the production of fluid inside the eye and increases the amount of fluid that drains from the eye, alleviating watery eyes. Decongestants are available in both over-the-counter and prescription forms. They should not be used for more than a few days, as overuse of decongestants can trigger a “rebound effect” that actually makes symptoms worse. Examples of decongestants include:
  
  
• • Naphazoline hydrochloride (Allerest, Vasocon)
    
    
  • Tetrahydrozoline hydrochloride (Eyesine, Murine Plus, Visine)
    
    
• Antihistamine/decongestant combinations. Combine the efforts of antihistamines and decongestants. These are available over-the-counter. Examples include naphazoline/pheniramine (Naphcon-A, Opcon-A, Visine-A).
  
  
• Nonsteroidal anti-inflammatory drugs (NSAIDs). Inhibit the body’s ability to produce chemicals called prostaglandins, which are released during an allergic reaction. Anti-inflammatories reduce eye pain, itching and swelling. They are available by prescription only. Examples include ketorolac (Acular) and nepafenac (Nevanac).
  
  
• Corticosteroids. Decreases inflammation during an allergic reaction by mimicking the behavior of cortisol, a hormone in the body that aids proper body function during stressful situations. They are only available by prescription. Examples include:
  
  
• • Prednisone acetate (EconoPred, Pred Forte)
  • Loteprednol etabonate (Alrex, Lotemax)
  • Fluorometholone (FML)
    
    
• Mast cell stabilizers (MCS) and MCS combination drops. Strengthen the mast cells to prevent them from releasing histamine and other chemicals that contribute to the symptoms of an allergic reaction. Mast cell stabilizers also reduce eye redness and wateriness. They are available in both over-the-counter and prescription form. Examples include:
  
  
• • Olopatadine hydrochloride (Patanol)
  • Ketotifen (Zaditor)
  • Azelastine (Astelin)
  • Pemirolast (Alamast)
  • Emedastine (Emadine)
  • Ketotifen (Zaditor)
  • Cromolyn (Crolom)
  • Lodoxamide (Alomide)
  • Nedocromil (Alocril)
  
  
• Artificial tears/saline solutions/ointments. Lubricate, dilute and wash away offending allergens. These medications also moisten the eyes, which frequently become dry as the result of redness and irritation. They are available in over-the-counter form in many brands, including:
  
  
• • Adsorbotear
  • Liquifilm Tears
  • Refresh
  • Tears Renewed
  • Visi White Petroleum Mineral Oil
    
    
• Antibiotics. Prescription medications used to treat bacterial infections. Those available in eye-drop form include:
  
  
• • Monofloxacin (Vigamox)
  • Gatafloxin (Zymar)
  • Ciprofloxacin (Cipro)
  • Erythromycin (Akne-Mycin, Erycette)
  • Gentamicin (Cidomycin, Genoptic)
  • Ofloxacin (Floxin, Ocuflox)
  • Sulfacetamide (Cetamide, Sulfex)
  • Tobramycin (Tobrex)
    
    
• Antivirals. Prescription medications used to treat viral infections, such as herpes eye infections. Those available in eyedrops include:
  
  
• • Adenine arabinoside (Vira-A)
  • Trifluridine (Viroptic)
  • Idoxuridine (Herplex Liquifilm)
  • Trifluorothymidine
    
    
• Glaucoma medications. Prescription eye drop medications used in the treatment of glaucoma (a disorder that involves optic nerve damage) include:
  
  
• • Betaxolol (Betoptic, Kerlone)
  • Dorzolamide (Trusopt)
  • Latanoprost (Xalatan)
  • Levobunolol (AKBeta, Betagan)
  • Metipranolol (OptiPranolol)
  • Pilocarpine (Carpine, Pilocar)
  • Timolol (Blocadren, Timoptic)
    
    
• Homeopathic medications. These alternative therapies use a very small dose of a substance in the belief that this will desensitize the eye to an allergen or irritant. The medical community considers such medications to be unproven. These medications do not have the approval of the Food and Drug Administration (FDA).

In addition, there are a number of medications in eye-drop form that may be used by an ophthalmologist (eye doctor) during an eye examination. These include medications to dilate (enlarge) the pupils of the eye or administer an anesthetic (painkiller). Dilating the eye allows the physician to view the inner eye while the anesthetic makes the examination comfortable for the patient.