Vasoconstrictors such as Visine, Clear Eyes and All Clear are over-the-counter eyedrops that are subject to misuse due to lack of consumer awareness and failure to read the labelling. This misuse can cause or exacerbate damage to the eye surfaces.
While these products are designed for occasional use for temporary relief of redness, they are not safe for regular use by anyone, and are particularly dangerous for people suffering from or at risk for dry eyes (as well as other groups such as those with open angle glaucoma).
First, vasoconstrictors have a rebound effect. You may think you're using them to get the red out, but they are known to cause or increase redness of the eyes if you keep using them. The FDA specifically says not to use them if your condition doesn't clear up within 72 hours, and warns that they may increase redness.
Second, vasoconstrictors are typically preserved with benzalkonium chloride, a powerful preservative that is highly toxic to the cornea. This preservative has been all but eliminated in lubricant products for people with dry eyes and is also increasingly falling into disfavor for use in prescription eyedrops requiring daily dosing such as glaucoma medications.
Third, any chronic redness needs to be investigated for its cause (which may range from conjunctivitis to dry eye) and treated properly. Self-treatment of eye redness with vasoconstrictors can not only delay diagnosis and treatment but can further damage the health of the eye surfaces at the same time.