Not only does castor oil soften the eye up, it also breaks down into undecylenic acid and sebacic acid, both of which powerfully inhibit calpain, the enzyme which causes progression of cataract. In fact castor oil is the industrial raw material for both of those substances.
So the castor oil we put in the eye must not ony be USP grade, but maybe also it should have been standing on the shelf for a few months so that it might contain a few percent of those two calpain inhibitors.
Undecylenic acid also mops up ROS (Reactive Oxygen Species) and prevents apoptosis of cells, maybe lens epithelial cells, so it would tend to help the lens continue to produce the chaperone protein alpha-crystallin. If you can shut down the bad enzyme and allow chaperone protein levels to rise, all thanks to the same single agent (castor oil), in theory, you can't lose. I am seriously thinking of alternating it with NAC.
Even more amazing, I found a story on the Web about a cataract cure in the Quran (Google "Medicine of Quran").
The curative agent here was the "secretion of human sweat glands". So far, I have been unable to find out more about that, however. Maybe someone else might have more luck. I wonder if the "Swiss pharmaceutical company" mentioned there was able to make it sterile, however.