Do you snuggle up with your smartphone or watch TV from the comfort of your bed? Blue-light emitting from digital devices may affect your sleep and cause sleep dysfunction, researchers have found.

The largest source of blue light is sunlight, but it's also found in most LED-based devices. Blue light boosts alertness and regulates our internal body clock or circadian rhythm, that tells our bodies when to sleep.

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This artificial light activates photoreceptors called intrinsically photosensitive retinal ganglion cells (ipRGCs), which suppresses melatonin.

Lead researcher of the study recommends limiting screen time, applying screen filters, wearing computer glasses that block blue light or use anti-reflective lenses to offset the effects of artificial light at night-time.

"By using blue blocking glasses we are decreasing input to the photoreceptors, so we can improve sleep and still continue to use our devices," said Lisa Ostrin, Assistant Professor at the University of Houston.

The participants of the study, published in the journal Ophthalmic and Physiological Optics, wore short wavelength-blocking glasses three hours before bedtime for two weeks, while still performing their nightly digital routine.

The results showed about 58 per cent increase in their night time melatonin levels, the chemical that signals your body that it's time to sleep.

Wearing activity and sleep monitors 24 hours a day, the study participants also reported sleeping better, falling asleep faster and even increased their sleep duration by 24 minutes a night, Ostrin mentioned.