http://glassbox-design.com/2010/vertex-lumina-led-review-optics/">http://glassbox-design.com/2010/vertex-lumina-led-review-optics/</a>
Here's a link to a review. They say they purposely chose not to use optics in order to more evenly spread light. I have to say that I don't keep any light hungry stuff on my sand bed, so I don't need high PAR down there.