I thought maybe there was a physical or psychological reason why they couldn't do it, especially since from what I saw in the article, they waited 2 years to have this approved and done? Could they have set a sort of pre-death will to say that the day a doctor confirms that they have gone completely blind, just put them down too? Maybe they could have had a bit more time or maybe even find a way to delay the blindness, were they able to see anything at all when they died?
To be deprived of one sense is bad enough, to lose another? I'm not sure I can say I'd want to live that way either. I'd be pretty much down for ending my life after losing my eyesight(as an artist, a writer, an avid reader and so forth, it's pretty damn significant).
I think it should be the right of every adult to choose when to end their life, with some counseling of course.