What was the color of Saint Paul's eyes?

Answer 1

We don't know as it is not mentioned.

It is thought that he was a shorter balding man with red hair, though that is speculation. Though, he was known for his great testimony and for his relationship with God, and not by his looks, however he may have appeared. In addition to the above, Paul himself, in his letters, speaks of his 'thorn in the flesh' - an affliction he had. Some believe that this was epilepsy, whilst others think that physically he had deformity. Early artistic depictions of Paul, some based on word of mouth passed on by generations, suggested that he was bow-legged, suggesting that his 'thorn' was rickets. however, the above writer was totally correct. He was known for his great testimony and for his relationship with God, and not by his looks. Look up an Orthodox Jew and notice his hair and enthnic characteristics and your looking at Shaul the Pharisee(Orthodox) Jew. Watch how he prays with the tefillin and other devices of Jewish worship. He would have been this way until the day he died.
Some traditions say he was not a tall man, had bowed legs and was balding.

Answer 2

Nothing in either scripture or tradition tells us the color of St. Paul's eyes.