Cataracts are layers over a person's eyes that prevent them from seeing properly. Cataracts usually develop because of old age or illness. The cause of cataracts may be the illuminate of the sunshine and ultraviolet. From the effect of ultraviolet, the phosphor ions may combine with the calcium ions of aging crystalline lenses to form the insoluble calcium phosphate. Then the crystalline lenses will get calcification and hard. When the crystalline lenses' protein is getting denaturation, the cataract has been caused. If the environment lights are too bright, it will also hurt your eyes of cataracts. You would eat more vegetables as spinach, broccoli, and cabbage mustard which full of anti-oxygen lutein and zeaxanthin to protect your eyes from the damage of sunshine and prevent it from to get the cataracts. These ways may strengthen sight in the eye with the cataract. As for the dizzy light, it is a over strong optical radiation which will hurt the eyes of people, to let the vision comes down till blindness.
The bright light environment will also cause cataracts. All sorts of reasons such as aging, genetic local dystrophy, immune and metabolic abnormalities, trauma and poisoning radiation can cause lens metabolic disorder which will cause lens protein denaturation and produce cloudy symptom. It is called cataract. The light is cloudy at lens. It is blocking which cannot cast in the retina and cannot see objects. The lens produces denaturation and cloudy and become opaque which will affect vision. The too bright light will stimulate the normal work of the retinal and crystalline lens. That is why it will cause the cataracts. You should protect the eyes carefully. Even if you are in the sun, you'd better wear the sunglasses to help you prevent from the uv rays and other bad lights. You should often eat the food with vitamin A and vitamin C which are good for the eyes.
It depends on what kind of bright light you are talking about and how bright it is. Not every kind of bright light can cause cataracts. It is more common to increase the risk of getting cataracts if long time exposing to UV radiation. As to some bright light, for example, the fluorescents with diffusers used in our daily life won't cause permanent damages to our eyes because the light spreads at a wide range instead of pointing at one direction. But bright light is indeed harmful to our health. Long time exposure to bright light might cause mania, which is very risky. Mania refers to a condition, which is an abnormal mood that people would get exaggerated emotion over a small stimulation. They could be too happy, too hyper or too stressed with rapid speech and have difficulty in concentration. Besides, bright light might cause problems like eye burn, sleep disturbance, eye strain and headache. In some serious cases, people might even have suicide thoughts.