The Prophet ﷺ said, "What is wrong with those people who look towards the sky during the prayer?" His talk grew stern while delivering this speech and he said, "They should stop (looking towards the sky during the prayer); otherwise their eyesight would be taken away." (Using translation from Bukhārī 750)
عَنِ النَّبِيِّ ﷺ أَنَّهُ قَالَ مَا بَالُ أَقْوَامٍ يَرْفَعُونَ أَبْصَارَهُمْ إِلَى السَّمَاءِ فِي صَلَاتِهِمْ قَالَ فَاشْتَدَّ قَوْلُهُ فِي ذَلِكَ حَتَّى قَالَ لَيَنْتَهُنَّ عَنْ ذَلِكَ أَوْ لَتُخْطَفَنَّ أَبْصَارُهُمْ