If the eye drops you buy at the pharmacy do not relieve symptoms, consult an ophthalmologist. Tears play a role in delivering oxygen and nutrients to the pupil (cornea) and killing bacteria that enter the eye, but too many eye drops can cause precious tears to be washed away. In addition, eye drops purchased at pharmacies for dry eye sufferers may not be injured by the effects of the ingredients, as these ingredients are not diluted by tears.