Staying hydrated — and why it’s important for your eyes

You know when you’re dehydrated. No matter what you do and how many litres of water you drink, you just can’t seem to take enough fluid in.

This is weird when you think that dehydration is when more water leaves the body than enters the body. The thing is, though, whereas water can only enter the body through one inlet in your face, it can leave the body in many, many, many different ways.

So, staying hydrated is a little more complicated than you’d first think. And although consuming your two and a half litres of H20 a day will help, it’s far from adequate to stay sufficiently hydrated.

Why it’s so hard to stay hydrated

Caffeine, high salt diets, screens, alcohol, diabetes, prescription meds, stress — there are innumerable parts of the modern lifestyle that, as well as simply not drinking enough water, lead to dehydration. And as your eyes contain about half a shot of water and rely on fluid to function, this means bad news for your vision.

Let’s take stress. When chronic, stress can exhaust the adrenal glands and in doing so decrease the production of aldosterone — a hormone that helps regulate the body’s level of fluid and electrolytes. You may recognise this process as tiredness, headaches, constant bathroom breaks, and a dry mouth, not to mention all the other all too familiar symptoms of stress.

Another one of the major H20 sappers is screens. Or more accurately, the amount of time people spend staring at computer screens, looking at their phones, and watching the television without even so much as looking up.

Screens in themselves aren’t harmful to your eyes. But using them for long periods is likely to lead to eyestrain and problems such as dry eye syndrome. It’s become so commonplace it now has its own name: digital eye strain. And it’s well documented which factors increase your chances of suffering from it — things like poor lighting, glare, and not taking breaks or blinking enough.

As you can see, our eyes literally take the strain of our modern lifestyles. But let’s now look more specifically at the role of water in the eyes and find out what exactly can happen if we fail to do our bit and keep them sufficiently topped up.

Keep the tears flowing

Biochemically, your tears are very similar to saliva — they contain water, minerals, and lipids, and possess several antibacterial and antiviral properties.

But unlike saliva, there’s not just one type of them. You have emotional tears that appear when watching a good drama or arguing with the spouse. Reflex tears that appear when its really windy or when you’re chopping onions. And basal tears, which are there sitting on the surface of your eye all the time.

These final tears are the ones that are most important for your general eye health as they protect, lubricate, and nourish the eyes throughout the day. When we’re dehydrated, though, it makes it difficult for your eyes to maintain a healthy layer of basal tears.

At first, this can mean dry eye, eye strain, and other vision problems. More worryingly, though, as it’s easier for dust, dirt, and other debris to enter your eyes, it means they can become red, inflamed, and as a result, develop painful and potentially vision-threatening eye infections.

Stay hydrated, keep your sight

Due to the eye’s high water content and heavy dependence on fluids to function healthily, your level of hydration is directly associated with your level of risk of certain common eye conditions and diseases.

The most common of which — probably something to do with that you’re reading this on a screen — is dry eye syndrome or keratoconjunctivitis sicca. The symptoms for dry eye syndrome include everything from dryness and a sensitivity to light to tearing and fatigue. The condition is also a risk factor for many other diseases including retinal vascular disease and cataracts.

Cataracts — the leading cause of blindness in the world — occurs when proteins that are naturally present in the eye coalesce and cloud an area of the lens. It’s not known exactly what causes cataracts, but activities that put strain on the body, and in doing so, promote dehydration, such as smoking, certain medications, and ultraviolet radiation, are known to play a huge role.

So remember, staying hydrated goes beyond your flashy water bottle. Change your habits today and make sure you keep your vision for tomorrow.