The Ocular “Heart Attack” of a Stare. (And why digital devices can cause these “heart attacks.”)
Why is staring at a screen like giving your eyes a “Heart Attack?”
Staring is the act of not blinking – so any activity that involves intense concentration is likely to induce staring. But sustained staring can be as bad a problem as a heart attack for your eyes!
To understand this, the first thing I point out to my patients is that the surface of your eye is a living surface – covered in living cells. Every living thing needs support and almost every living cell in your body gets that support from blood. Since we can’t see through blood, we have this wonderful thing called tears – basically like clear blood for those living cells that help us see. Fortunately, when our eyes are open, they are exposed to the oxygen in the air they come in contact with, so we don’t need red cells in our bloodstream – but much of the rest of our blood products are in our tears and the best tear is made of water, salt, protein and oil – the “salad dressing” we use for that clear blood-like product we call a tear.
Since tears are literally the “lifeblood” of that surface, then a blink is literally the “heartbeat” that circulates the tears over that surface. The old, used up tear that has nourished, lubricated, protected, and hydrated the surface is blinked away, down little tear ducts that “pump” the tears down the back of our throat (hence the salty taste we get when we activate that salty “firehose” called “reflex tearing” or most call actively crying). The fresh, healthy tear that has yet to do any “work” sits in the little “gutter” between our eyeball and the lower lids. Blinking compresses the tear drainage system (activating the “pump” that sucks the tears down our throat) but also brings the fresh, healthy tear up from that gutter to put a new dose of tears where they are needed. I’ve addressed how that tear reservoir becomes compromised by conjunctival chalasis (the loose membrane I’ve addressed in my earlier postings), but poor (weak) or partial blinking is like having a weak heartbeat and staring is like not having a heartbeat – hence a “heart attack!
Those who spend a lot of their time on digital devices almost always suffer from some of this problem (staring too much) – and while staring, the old, used up tear becomes increasingly compromised from evaporation (I’ve also posted on evaporative dry eye and the related oil problems). Evaporation leads to concentration of the tears (increasing salt levels) and dryness, which leads to irritation and then inflammation (the body’s defense response to irritation - also addressed in earlier posts). Irritation hurts the tiny tear glands making the tears, which progressively leads to increasing degrees of dry eye disease (the vicious cycle).
Next week I’ll relate my typical prescription to avoid this “heart attack.”