We’re all probably guilty of sitting a little too close to our screens whether you’re a designer and your monitor is too big for your desk or if you were just yelled at by your mom by having your face practically smushed against the TV while you’re watching IPL. But what exactly qualifies us too close as the public has commonly believed?

So, a big part of the reason people worry about whether sitting too close can hurt their eyes is that many of us feel eyestrain when we’re staring at something for far too long. Eyestrain is a natural consequence of attempting to focus on just one thing for long periods of time and if you’re sitting close to a screen, chances are you’re hyper-focused on wherever it is you’re looking at, say a tense moment in a sporting event, but why does focusing on something for a long time makes your eyes hurt? It turns out that the mechanism for this incompletely understood but it’s thought that because your eyes are trying to intensely maintain their focus for so long it ends up overworking your Ciliary Muscles, these are the muscles that control the shape and curvature of the crystalline lens and near the front of your eye so that they can properly focus. Looking at something close by causes them to contract so it’s natural that they might tire out, just think about how sore your other muscles get after a hard day at the gym. However, the good news is that this has never been demonstrated to cause permanent eye damage in adults, and if you’re worried about brightness that probably not a big deal either as everyday electronic screens simply don’t appear to get bright enough to cause retinal damage, although it might be unpleasant to use a smartphone at full brightness in a dark room, it’s nowhere close to saying staring at the eclipse like Donald J Trump or doing something stupid with a laser pointer.

But if you’ve teenage siblings or children, keep in mind some studies have suggested that excessively focusing on objects too close to them can cause near-sightedness or Myopia later in life because their eye is still growing at that age and this isn’t limited to sitting too close to electronic screens, even if they’re spending too much time with a book that can cause problems too so make sure they’re resting their eyes enough.

Of course, eyestrain is still annoying even if it isn’t actually harmful to adults in the long-term so if you’re suffering from tired eyes after yet another hour of playing PUBG, give your eyes a break and maybe go outside* where you’ll probably be paying attention to objects that are more distant from you. Another good idea is to use a reputable brand of eye drops since when you’re focusing on things close to you for long periods, your eyes tend to dry out because you’re not blinking as much.

There are far greater health concerns from staring at a screen all day like maintaining poor posture.