“Sand” and scratchy eyes are not cause and effect but are both the result of irritation.
The so-called sand, or “sleep” that builds up at the corners of the eyes is actually dried mucus.
If the eyes are irritated for any reason, pollution or dryness, for example, more mucus is secreted, and the longer the eyes are exposed to the irritant over the course of the day, the more mucus builds up.
Overnight, the eyes themselves stay fairly moist with tears, because the lids are closed, but the mucus collects in the corners and dries out.
Related Posts
-
Why Do Some People Wake Up Tired After a Full Night’s Sleep But Feel Better As the Day Wears On?
The way a person feels when waking up from sleep, day or night, depends largely on the sleep stage the person was in just before waking up. This "sleep inertia" affects how someone…
-
How Do Your Eyes Grow, When Do Your Eyes Stop Growing, and Why Do Eyes Change Their Shape?
Human eyes do grow, but most of the growth takes place early in life. For the retina, a vast majority of growth takes place before the age of two. For the eyeball, most…
-
What Causes Crusty Eyes When You Wake Up In the Morning and Where Does the Sand or Sleep Come From?
The scientific term for the yellowish crystalline substance sometimes found encrusted on eyelids when you wake up is "Rheum", or gound. It is also commonly referred to as "sand" or "sleep". Some amount…
-
Why is video from the space shuttle clear but audio is scratchy like transmissions from the sixties?
It has largely to do with the fidelity of the microphones, not the quality of space-to-ground communications systems. The astronauts wear wireless mikes that are as light and unobtrusive as NASA can make…
-
Where did Hurricane Sandy Come From?
The origins of Hurricane Sandy, one of the most costly superstorms ever, have been revealed by meteorologists. The storm caused over $20 billion (£12.5 billion) worth of damage and claimed more than 50…
-
Why Don’t People Wake Themselves Up When They Snore and Do People Who Snore Know They’re Snoring?
A vast majority of snorers are in fact men, and may be waking up hundreds of times a night without remembering it in the morning. Snoring in its worst form is a symptom…
