How did Galileo Galilei continue working after he became blind?

After Galileo Galilei became blind, he continued his scientific work by collaborating with a young student named Vincenzo Viviani, who assisted him until his death in 1642.1

Despite his failing health and the constraints of his house arrest in Arcetri, Galileo remained intellectually active. He had begun writing a new book on the sciences of motion and the strength of materials while in Siena, and he continued to develop these studies during his final years. This work, titled Dialogues Concerning Two New Sciences, was eventually smuggled out of Italy and published in the Netherlands in 1638. In this text, he summarized his experimental investigations into the law of falling bodies and the parabolic motion of projectiles, marking a significant contribution to the field of mechanics.1