Based on the scientific research I've done, I would consider Eyebright Plus to be an excellent product, since it contains bilberry, mixed carotenoids and lutein (which also helps prevent macular degeneration).
The following nutrients are also very important:

Vitamin C - greater than 1,000mg/day - long-term high intake as been linked to a substantial reduction in cataract risk

Bilberry and Vitamin E were shown to stop cataract formation in 49 of 50 patients in one study

Beta-carotene acts as a special filter, protecting the lens of the eye from excessive oxidation