When and why was Paul struck blind?

Within a few years of Jesus’ death and resurrection Paul (who was called Saul at the time) was struck blind when he was on his way to Damascus:

{3} Now as he went on his way, he approached Damascus, and suddenly a light from heaven flashed around him. […] {8} Saul rose from the ground, and although his eyes were opened, he saw nothing. So they led him by the hand and brought him into Damascus. {9} And for three days he was without sight, and neither ate nor drank. (Acts 9:3,8-9)

We aren’t specifically told why Paul was made blind for three days. One possibility is that it gave him time to consider the amazing experience he had on the road to Damascus, where he met Jesus (Acts 9:4-6), and to reflect on — and repent of — his life in opposition to God. The ‘three days’ of blindness may have made him think specifically about Jesus’ death (when he was in the grave for ‘three days and three nights’) and the part his people played in it (Mat. 16:21), which would have helped him repent of his own sinful life (similar to the experience of the people in Acts 2:36-38).