Question:  “Why do people close their eyes when praying, is it biblical?

Answer: “To you I lift up my eyes, O you who are enthroned in the heavens! As the eyes of servants look to the hand of their master, as the eyes of a maid to the hand of her mistress, so our eyes look to the LORD our God, until he has mercy upon us (Psalm 123: 1, 2, NRSV).

“And the publican, standing afar off, would not lift up so much as his eyes unto heaven, but smote upon his breast, saying, God be merciful to me a sinner” (Luke 18:13, KJV).

The first Scripture indicates that our eyes should look to God; the second verse, that we are not worthy to look to God. When we close our eyes in prayer we recognize our unworthiness, like the publican. We also free ourselves from any distractions so that our minds can be focused on looking to God as indicated in the first Scripture.