Tired, fatigued or sore eyes can be associated with a variety of causes such as dry eye disease, computer vision syndrome or even lack of sleep.
While the feeling of not being able to keep your eyes open can often be due to purely a lack of sleep, if only your eyes feel tired or sore it could be a sign of dry eye disease.
Eye fatigue/strain while focusing
If you experience eye fatigue due to dry eye it is likely related to certain tasks which require more focus such as reading, writing, or working on a computer or screen. When you perform tasks such as these you tend to blink less. Blinking less means that your eyes are not getting the oily layer of tears as these are spread across the surface of your eye by little glands in your eyelids (Meibomian glands) every time you blink. If you have dry eye, performing tasks such as these can worsen dry eye symptoms, tired eyes being one of them.
Additionally, when you work on a computer your eyes can experience fatigue because they are having to constantly stay focused at something with a fixed distance. After a period of time you may experience eye strain, which, when coupled with a decreased blink rate can lead to tired or sore eyes.
Practice the 20/20/20 rule
When you know you will be working behind a screen for an extended period of time, do your best to avoid eye strain by practicing the 20/20/20 rule. Every 20 minutes, stare at an object 20 feet away for 20 seconds. After doing this take a few long blinks to make sure your eyes can fully ‘reset’ every so often.
In case of a sudden onset of symptoms, contact your eye doctor
Tired eyes may be quite common if you regularly get a lack of sleep, experience dry eye or spend a lot of time behind the computer. If you do experience a sudden onset of symptoms which seem unrelated to the previously listed scenarios or any extreme symptoms of heavy eyelids, eye fatigue, eye pain or intense soreness contact your eye doctor for advice.