The Blind Musician by Vladimir Korolenko

Their guests had once more left them, and life returned to its usual regularity at the Popèlski manor; but the temper of the blind man had undergone a decided change. It had become variable and easily agitated. When at times his happy moments rose vividly before him, he grew more cheerful, and his face brightened. But this did not last long; and in the course of time even these cheerful moments were dimmed by the fear that they were about to vanish, never to return. Thus his temper grew very uneven; outbursts of demonstrative affection and of extreme nervous excitement were often succeeded by days of secret gloom and melancholy. And at last the mother's worst fears were realized -- the fevered dreams of childhood returned to the youth.

One morning Anna Michàilovna went into her son's room. He was still sleeping, but with a strange and restless sort of slumber. His eyes were partly open, and seemed to peer from beneath his eyelids; his face was pale, and wore an expression of alarm.