Most glaucoma eye drops cause side effects, and some effects result from the preservatives used in nearly all prescription eye drops. Many who have side effects from using glaucoma drops stop taking the medication and fail to inform their eye doctors. However, this may ultimately result in damage from the high pressure in the eye and lead to vision loss. Anyone with side effects should inform her eye doctor to determine if he can recommend another option.
Allergic Reaction
People who have a history of allergic reactions to preservatives should discuss this with an eye doctor prior to using the glaucoma medications. Some people may have an allergic reaction to the medication or the preservatives. This may cause redness, irritation and swelling, says The Foundation of the American Academy of Ophthalmology. If a person has any signs of allergic reaction, she should contact her eye doctor immediately. However, since many glaucoma eye drops cause redness and surface irritation, an eye doctor may recommend continuing eye drops despite the side effects, and as long as the symptoms do not worsen.
Eye Changes
Some glaucoma medications may cause noticeable changes to the outward appearance of the eye. For instance, a person using some drops may notice a change in the color of her eyes, says the Glaucoma Research Foundation. In most people with eye color change, the color will gradually turn to brown. Eye color does not usually return to "normal" if the person stops using the drops, and the color will remain brown. As well, many people experience a thickening of eyelashes. If a person stops using an eye drop that causes increase eyelash production, the eyelashes will thin after discontinuing the drops. Though the changes in eye appearance result from the medications themselves, these drops do contain preservatives.
Systemic Effects
The components of eye drops can travel throughout the body and cause a reaction, called a systemic reaction. This occurs through the tear ducts. The excess eye drops drain through the ducts and down the back of the throat, into the stomach. If a person has an allergic reaction to preservatives or the medication contained in the eye drop, she may experience side effects such as stomach and gastric upset. As well, some glaucoma medications may cause changes in heart rate, blood pressure, disorientation and breathing problems, says the University of Illinois at Chicago.
