Cement splashes into eyes — alkali burn; 30 minutes of irrigation before anything else. Alkali (cement, lime — liquefactive necrosis, penetrates deep) is worse than acid (coagulative — self-limiting): first aid is immediate copious irrigation (20–30 min, any clean water — don't wait for the hospital), then check pH, then specialist care (steroids, ascorbate, amniotic membrane). Foreign body (grinding — remove at slit-lamp, burr the rust ring; never at home with a needle). Globe rupture (teardrop pupil, uveal prolapse — shield without pressure, NPO, tetanus, emergency repair). The tap water is the treatment — irrigation before examination.