One of Ikrima's companions reported that the Prophet ﷺ used to glance sideways during the prayer. He then mentioned something similar.
حدثنا محمود بن غيلان حدثنا وكيع
عن بعض أصحاب عكرمة أن النبي ﷺ كان يلحظ في الصلاة فذكر نحوه
No references are available.
[Hasan] See the previous hadith. There are also narrations on this topic from Anas [to come: 589] and Ayesha [to come: 590].