A cataract is something that develops inside the human eye and causes cloudy vision. Usually, cataracts do not impair the vision until they have been growing inside the eye for quite some time, as stated by Mayo Clinic.
Cataracts can cause more than just blurry vision; other symptoms can happen as well. Some of the additional symptoms that cataracts can cause include light sensitivity, double vision and an increased change in glasses prescriptions. The double vision that cataracts can cause usually only occurs in one eye and can also cause light to have glare around it. This is often referred to as a "halo," as stated by Mayo Clinic.