Q: I have a disease which is causing me to go blind. What is the spiritual meaning of blindness? How can I deal with this distressful situation?
A: G-d's Divine Providence over each and every one of his creations is called "The eyes of G-d on all of his creations." Even though a person cannot see, G-d's eyes are always upon us.
In the Talmud, a blind person is called "sagi nahor," which means "much light." The blind person has too much light for our world. This concept appears in allegorical form in the Story of the Seven Beggars by Rabbi Nachman of Breslov. See the story of the blind beggar who appears on the first day of the wedding festivities.
When we recite the Shema Yisrael, we close our eyes, in order to be able to "see" G-d, as it were. The word "shema," which means "hear," is also an acronym for "Se'u marom aynaychem," Lift up your eyes, (and see Who created all of these things.)
Isaac lost his ability to see, and yet in the future it is specifically to him that the Jewish people will say, "Because you are our father."
Nevertheless, your situation is obviously very painful. Pray with heartfelt emotion to G-d to return your sense of sight, and may G-d, in His goodness, hear and answer your prayers. Even though it is difficult for us to understand G-d's wondrous ways, it is important for you to strengthen you faith and confidence in Him, that all that happens to you is for your ultimate good! It is also always important to help others in situations similar to yours.