Hudhayl bin Shurahbil (may Allah have mercy on him) says that Sayyiduna Sa'd bin Mu'adh (may Allah be pleased with him) came to the Prophet (peace and blessings be upon him) and sought permission while standing facing the door. He (peace and blessings be upon him) moved him to one side with his hand and said: "Seek permission like this; permission has been prescribed only because of sight."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الأشربة والحد فيها / 17661