Many of us have more light pollution exposure than we realize. Numerous articles have been written discussing the benefits of sleeping in absolute darkness.
The more your sleep is disrupted by light pollution, the lower your melatonin levels and the greater your risk of developing cancer becomes. In fact, one of the first studies linking cancer to light showed that blind women have a 36 percent lower risk of breast cancer compared to sighted women. Why? Because they are unreceptive to light. This means that their bodies maintain high melatonin levels at night regardless of how much light is in the room. — Dr. Joseph Mercola 
Dave Asprey has discussed the importance of sleeping in a dark environment extensively in his podcasts. 
Unfortunately, we can’t always control the amount of light in the room where we sleep. A simple solution for eliminating the amount of light exposure to our eyes is to use a sleep mask or an herbal eye pillow.
As I discussed here, the use of lavender essential oil can greatly enhance sleep quality, so I like to combine the use of lavender with the light elimination properties of an eye pillow.
The following recipe was adapted from Organic Body Care by Stephanie Tourles. 
Make a soft fabric pillow 4 inches by 10 inches, leaving a small opening to insert the herbal stuffing.
Herbal stuffing ingredients:
- 1/2 cup whole flax seeds
- 1/2 cup lavender flower buds (dried)
- 1/2 cup peppermint leaves (dried)
- 1/2 cup crushed rose petals (dried)
- 15 drops lavender essential oil
Place stuffing into the pillow and then sew the opening closed.
To use: Place the eye pillow over both eyes and the bridge of the nose and go to sleep. Stephanie Tourles suggests chilling the eye pillow for 30 minutes if your bedroom is too warm.