This episode is well-acted and pushes the obvious buttons. However, why they chose to take the show in this direction might not be so obvious. A significant amount of time passed since Mary simply started wearing glasses, and that was the extent of her vision problem. Since then, Mary was shown without glasses in several episodes, and her vision problem not referred to at all. All of a sudden, Mary is going blind. What a bummer! The episode is superlative in terms of the performances, but the story was an obvious setup for taking the show in a different direction. There was also an unneeded subplot of Laura meeting a new guy, who then starts to like Mary. Laura starts to resent Mary, even spewing some hateful words about her sister. However, this situation is not followed up on. It seemed to be simply forgotten about, in light of the bigger tragedy. Didn't make much sense. But, of course, everyone would tune in for Part 2.
