Vision, the ultimate “tool” of a painter
Claude Monet had been suffering from cataracts since 1912. From 1912 to 1922, Monet was usually complaining to his friends about his failing vision and the fact that he was not able to distinguish colours. The diagnosed cataracts led to "blurry" images which are represented through his art. Given that Monet was already an Impressionist, his paintings of this period in particular, ended up as "a fuzzy riot of color". Examining these paintings, the use of stronger colours - which opposed the painter's style - and also the yellowish and brownish results are the effects of the disease, which made him incapable of selecting his palette properly.
After the operations in 1923 which cured his cataracts, Monet destroyed many of his previous paintings. However, he was so excited about his cured vision, that he excused himself to his friend André Barbier saying:
"I must be free at 10 in the morning to go back to work. This is for me an unsurpassable joy. Since your last visit my sight is a lot better. I work as never before and I am very satisfied with what I am doing. If my lenses were even better, I could only wish to live until I am one hundred years old."
The differences between Monet's paintings during the period of his failing vision and after he was cured are clear especially amongst those two examples of The Japanese Footbridge and The House among the Roses. Noticing the brownish and strong colours he used for the first one in 1920-1922, compared with the varied palette and the "freely breathing" colours of the second one from 1925, we are able to see the effects of the problem and also Monet's excitement after the operations.
References: Thomson, A. (2007), "The Blurry World of Claude Monet Recreated", Live Science, Available at: http://www.livescience.com/1512-blurry-world-claude-monet-recreated.html