http://3dprintingindustry.com/2015/02/26/luxexcels-transparent-3d-printing-service-made-public
I haven't looked into price, quality, or turn around time, but this looks like an interesting prospect for custom optics design.LUXeXceL has previously won awards for its one-of-a-kind Printoptical 3D printing technology. With the ability to 3D print clear parts up to 20 mm in height, without the need for post-processing, LUXeXceL is the only company currently offering the ability to 3D print optical components. And, after establishing a 1,000 sqm mass optics printing facility in Kruiningen, the Netherlands last year, the Dutch company is now opening up its transparent parts printing service to the public.