Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Mean (± standard error) change in melatonin concentration (emmetropes, filled circles; myopes, open circles) and cortisol concentration (emmetropes, filled squares; myopes, open squares) across 24 hours; gray area represents the dark period.
