Why do planes dim cabin lights before night landing?

Answer: Helps eyes adjust to darkness outside

Helps eyes adjust to darkness outside ✓ — Correct! Your eyes need 20-30 minutes to fully adapt to darkness. Dimming lights lets pupils dilate and rod cells become more sensitive. If emergency evacuation is needed, passengers can immediately see emergency lighting and exits rather than stumbling blindly while eyes adjust.

Pilots need less light reflection — Wrong. The cockpit is separate from cabin lighting. Dimming is for passenger safety—pre-adapting eyes to darkness so they can see emergency exits and lighting immediately if evacuation becomes necessary.

Signals passengers that landing is near — Wrong. While dimming does happen before landing, it's not merely a signal. It's a critical safety measure allowing eyes to adapt to darkness. Announcements and seatbelt signs notify passengers of descent—dimming serves the specific purpose of dark adaptation for emergency preparedness.