目薬

1. Origins, structure, and basic meaning

• Structure: 目薬 (めぐすり) is the compound noun eye drops or eye medication.
• Basic usage: 目薬を一滴さす administers one drop; 目薬を鞄に入れてある describes keeping the medicine in a bag.

2. Common pitfalls and similar expressions

• Applying drops with さす
  • The conventional verb is 目薬をさす; 一滴 counts the dose, while 入れてある describes a prepared storage state.