There is evidence that the visine may cause glaucoma, some researchers believe that overdose of eyedrops containing visine can contribute to a blockage in the normal flow of fluid, and with long time use of visine drops, thus you may get glaucoma. Usually, you will not notice the symptoms of glaucoma until the condition has already become worse, since early symptoms can resemble frequent headaches. Besides, visine eye drops also have many side effects. The most common side effect of visine is that long-term use of visine can actually cause the eyes to appear redder because the active ingredient in visine acts will constrict the blood vessels. Visine also reduces bloodflow and oxygenation to the surface of the eye, which also causes stinging of the eye upon instillation. What's worse, long-term use of visine may also damage the ocular surface. Additionally, visine can cause many problems, including vomiting, serious reductions in blood pressure and heart rate, and even coma. Therefore, to prevent glaucoma caused by visine, you should reduce the use of visine eye drops meanwhile take physical exercises to maintain a healthy life style.