So under the opt-out system, consent from the family is not requested/obtained?
I don't know if in practice it is in those countries that already operate the opt out system; I'm saying it shouldn't be. The decision to donate organs is pure altruism and rests with and only with the temporary caretaker of said organs. Nobody else gets a say. Sorry, but that's how it should be. If families think that decomposition or roasting of organs is preferable to giving several other people a chance of sight or even of life itself ... well fuck them, frankly.
If that seems harsh, well done on your perspicacity: it is. Hard? Yes. But life is hard and so is death - welcome to the universe. Some people, recently bereaved, find that the whole business is made easier by knowing that the person they've loved and just lost was large-hearted enough to want to do an unalloyed and unambiguous good for complete strangers. If you say to me, while still living, that you prefer not to help others, or relatives say the same of a loved one, I put you and them in the same category as the farmer who would rather see a crop rot in the ground than feed people with it. (This is already the case with supermarkets). I have no option but to accept that decision, but I am under no obligation to respect it or regard it as anything other than contemptible.
I don't really expend tremendous effort to disguise my utter scorn and contempt for stupid, ignorant and irrational beliefs, and to me, believing that it's better to deny people a chance - any chance - of better eyesight or of living an extended (or even a normal) lifespan is right up there in the ranks of nauseating ignorance not to mention equally sick-making selfishness. (What corpse needs internal organs, and what for?). Especially in the name of religion, pretty well all religions supposedly being predicated on the idea of good will and charity to others, whether mandated by a god, two gods, many gods or no gods.
But then religion is usually best at talking a good game rather than actually delivering good where it counts - with real live people actually living in the world. That's why overwhelmingly we find a certain type of person more interested in stem cells and embryos than somebody who goes ouch if you pinch them.
But why not an opt-out DNA or biometric data based system with the known advantages of such?
If it genuinely is opt out, then fine.
There are also known disadvantages, of course.