Light resets the eye’s internal clock even without rods, cones, or melanopsin

Retinas of Opn4(-/-);rd1/rd1 mice synchronize to light/dark cycles independently of the brain's master circadian pacemaker.

• The mammalian retina functions as its own circadian clock.
• Lighting cycles can entrain the retinal circadian clock in vitro without the involvement of rods, cones, or melanopsin.
• In vivo observations indicate that retinal synchronization occurs regardless of the master circadian pacemaker's phase.
• This suggests that the retina may utilize a distinct mechanism for local circadian entrainment compared to the overall organismal rhythm.

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