أَخْبَرَنَا عُبَيْدُ اللَّهِ بْنُ سَعِيدٍ، وَشُعَيْبُ بْنُ يُوسُفَ، عَنْ يَحْيَى، - وَهُوَ ابْنُ سَعِيدٍ الْقَطَّانُ - عَنِ ابْنِ أَبِي عَرُوبَةَ، عَنْ قَتَادَةَ، عَنْ أَنَسِ بْنِ مَالِكٍ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏"‏ مَا بَالُ أَقْوَامٍ يَرْفَعُونَ أَبْصَارَهُمْ إِلَى السَّمَاءِ فِي صَلاَتِهِمْ ‏"‏ ‏.‏ فَاشْتَدَّ قَوْلُهُ فِي ذَلِكَ حَتَّى قَالَ ‏"‏ لَيَنْتَهُنَّ عَنْ ذَلِكَ أَوْ لَتُخْطَفَنَّ أَبْصَارُهُمْ ‏"‏ ‏.‏

It was narrated from Anas bin Malik that: The Messenger of Allah (PBUH) said: "What is the matter with people who lift their gaze to the sky when praying?" And he spoke sternly concerning that until he said: "They must stop that or they will certainly lose their eyesight." Translation Not Available

Book Ref: Sunan An Nisai Book 13 Hadith 1193
Web Ref:  Sunan An Nisai Vol 2 Book 13 Hadith 1194