By this, it is not meant to glance to the right or left without turning the neck, because the Prophet صلی اللہ علیہ وسلم would sometimes, when necessary, turn during his prayer without turning his neck behind his back.

Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrates that the Messenger of Allah (peace be upon him) used to glance to the right and left in his prayer, but he would not turn his neck behind his back. Imam Abu Bakr (may Allah have mercy on him) says that the statement of Sayyiduna Ibn Abbas (may Allah be pleased with them both), "The Prophet (peace be upon him) used to glance in his prayer," means that he would look to the right and left with his eyes.