Matthew 20:30
Two blind men were sitting by the roadside, and when they heard that Jesus was going by, they shouted, “Lord, Son of David, have mercy on us!”
Many Torah observant Jews recognized the Messiah. Not by His looks, neither by His Earthly belongings. But because the Messiah fulfilled the prophecies. He was supposed to come from the bloodline of King David. Thats why they cried out to the Son of David.
Banjara Origin News 
They may have been physically blind, but fortunately for them, they had the eyes of faith.