Staring at a backlit screen has become an almost inescapable part of life in the early 21st century

According to VisionCare NSW, more than half a million Australians are vision-impaired by the age of 40, and about three quarters of these cases are preventable.

So what's behind these stats? Something called refractive error has to take a lot of the blame. The name might sound vaguely cool, but it's not something you want as a friend. Refractive error is what happens when light doesn't focus properly inside the eye. And staring at a backlit screen, whether it's on a laptop, tablet or mobile phone, is a very common day-to-day culprit for refractive error.

Staring at a backlit screen has become an almost inescapable part of life in the early 21st century. So much of your TAFE studies probably involve online research. And then there's the actual typing up of your assignments - more time staring at a screen (especially if you're a slow typer). And that's not even mentioning time spent on social networking sites. At this rate, we might all be wearing specs by the time we're 40.

Not to worry. There's plenty of things you can do to look after your eyes that are simple, easy and won't cost you a cent. Here's a couple of suggestions.

Good lighting

Excessively bright light isn't great for your eyes, especially over a lengthy period of time. When you're in front of your computer screen, try to set the ambient (surrounding) light at roughly half that of the average fluroscent-lit office environment.

Blink

Blinking is important because it keeps your eyes from drying out. But when you're staring at a computer screen you only blink at about a third the usual rate. So every 20 minutes or so, slowly blink your eyes 10 times as if falling asleep.

Eye exercises

Focusing intently on your computer screen can be like boot camp for your eyes. Try what eye doctors sometimes call the 20-20-20 rule. Every 20 minutes, look away from your screen and focus on something that's about 20 feet (six metres) away for about 20 seconds. This will relax your eyes' focusing muscles.