There isn’t thought to be a way to actually prevent cataracts. However, there are a variety of things that doctors think can be done to help reduce the risk of getting cataracts(1).
So, although, you can’t categorically prevent cataracts, there are ways to help reduce the risk of getting them.
Glasses – Why do I need glasses after cataract surgery?
Surgery – What does an eye look like after cataract surgery?
Surgery – How is a cataract operation performed?
Near-sighted – Does cataract surgery correct near-sightedness?