The Prophet ﷺ said, "Does any of you not fear, when he raises his head during the prayer, that his sight may not return to him?"
حدثنا محمد بن جعفر حدثنا شعبة عن سليمان عن المسيب بن رافع عن تميم بن طرفة
عن النبي ﷺ أنه قال أما يخشى أحدكم إذا رفع رأسه وهو في الصلاة أن لا يرجع إليه بصره
Its isnad is sahih, all its narrators are trustworthy. Muslim narrated it, 1/321, no. 428, as did Abu Dawud, 1/239, no. 912, and Ibn Majah, 1/332, no. 1045, all in the chapter on prayer, on the prohibition of raising the gaze.