四分律刪繁補闕行事鈔 2.328

2.328

繫鉢想食者，謂非左右顧視。不犯者：有病、比座眼闇如前戒、日過、難緣者。

Eating with mind focused on the bowl means not looking around left and right. One does not commit an offense if: having an illness, the neighbor is visually impaired as in the previous precept, the time is expiring, or under perilous circumstances.