When you experience a gradual blurring or dimming of vision, you may have the earliest symptoms of a cataract. You may also see “halos” around lights. A cataract is any clouding or opacity in the normally transparent eye lens. Most cataracts develop as part of the aging process as the chemical composition of the lens changes. Studies have also shown that prolonged exposure to sunlight over many years (particularly the ultraviolet-B rays) can hasten the development of cataracts. Cataracts can occur at any age and may be due to an eye injury, certain eye diseases, medical conditions (such as diabetes), heredity, birth defects, some medications (such as steroids), excessive alcohol consumption, and smoking.
P.S. In the early stages of a cataract, stronger lighting and eyeglasses can help with blurred vision. When impaired vision interferes with your usual activities, safe and effective cataract surgery is the best answer.