I have a son who is completely blind so I know how you feel. Anyway, there is something called Barlean's Omega swirl and it is contaminant and mercury free and tastes as yummy as candy.
It has 730mg of EPA/DHA per 2 teaspoons (10ml). It tastes great so you are not filled with dread when you have to take it. It is sweetened with Xylitol.
There is another product you might want to look at called Macushield because it contains Meso-zeaxanthin (10mg), Lutein (10mg), Zeaxanthin (2mg). I take it but have not tried it long enough to see the results yet. Here is a website in the UK (not sure about the US). http://www.edinburgh-eyetests.co.uk/order-MacuShield.htm
I am also hoping for progress with stem cell research so that they can help my son with Leber's Amaurosis. He has been blind since birth because of faulty rods and cones. Miracles do happen I guess. They have been partially successful with this type of stem cell research in repairing the retina but it is only for repairing existing cells and not for the growth of whole new ones, which is what my son needs.