Every 20 minutes of looking at the screen, look at something 20 feet away for 20 seconds. Also, try to blink a lot.
Using a larger font to read helps to reduce eye strain. Adjusting your brightness helps, usually brighter screens are better in brighter rooms, dimmer screens are better in dark rooms.
Also, try to make your computer screen lower than your eyes; more of your eye is covered by your eyelid when you look down, so there will be more lubrication and you will subconsciously blink more.
Eat foods with vitamin A, which helps with the health of your eyes. See this question for more.
The health of your eyesight when using computer it really depends what kind of screen you're using and many other factors (DNA, diet, etc.), but in general, modern monitors (such as LCD, LED-backlit, white-LED, OLED) does nothing to the health of your eyes, unless you're still using CRT monitor. The bigger issue is rather neck and back if you don't site properly.
Remember, if you feel your eyes are not comfortable, you may adjust the brightness and contrast of your screen.
If you're using computer for too long, it's completely normal that your eyes would be tired and it really depends on the person (professionals can spent 8-12 everyday for years and their eyesight is perfect, for other 1h is enough).
In this case, you simply need a rest. It's usually advice to do short breaks and take a fresh air. You may also consider to train your eye muscles as a number of ophthalmologists believe that an exercise programme based on something called the Bates Method may keep eyes in better shape.
See: Can you really train your eyes to see better? where we can read:
Some of the principles of the Bates Method are already accepted by mainstream eye care.
More information about older monitors:
If you're using CRT most people experience mild discomfort unless the refresh rate is set to 72 Hz or higher. A rate of 100 Hz is comfortable at almost any size. It's usually advice to have a screen protector. However CRT are long lost technologies and this doesn't apply anymore to LCD monitors.
There are some options you have to reduce eye strain.
You can get an anti glare cover for your monitor
You can also adjust lighting of your work area (not always possible) by lowering internal lighting and blocking external lighting.
You can adjust the setting of your monitor to make the brightness
similar to your surroundings which will help with strain
You can blink more often to keep your eyes from drying out You can
take breaks both by leaving your computer or by moving your eyes
around the room/desk and avoiding your computer every once in a
You can set up your desk to make sure printed material is in easy eye reach and lighted similarly
You can look into getting specialized gaming/computer glasses which
are designed to reduce eye strain and fatigue
You can also use f.lux, it is a software that adjusts automatically and according to your location the brightness and contrast of your monitor. It lowers UV light during day, and lowers IR light during night.
The American Optometric Association (referenced above) recommends the following changes in viewing habits to alleviate symptoms:
Some important factors in preventing or reducing the symptoms of CVS have to do with the computer and how it is used. This includes lighting conditions, chair comfort, location of reference materials, position of the monitor, and the use of rest breaks.
- Location of computer screen - Most people find it more comfortable to view a computer when the eyes are looking downward. Optimally, the computer screen should be 15 to 20 degrees below eye level (about 4 or 5 inches) as measured from the center of the screen and 20 to 28 inches from the eyes.
- Reference materials - These materials should be located above the keyboard and below the monitor. If this is not possible, a document holder can be used beside the monitor. The goal is to position the documents so you do not need to move your head to look from the document to the screen.
- Lighting - Position the computer screen to avoid glare, particularly from overhead lighting or windows. Use blinds or drapes on windows and replace the light bulbs in desk lamps with bulbs of lower wattage.
- Anti-glare screens - If there is no way to minimize glare from light sources, consider using a screen glare filter. These filters decrease the amount of light reflected from the screen.
- Seating position - Chairs should be comfortably padded and conform to the body. Chair height should be adjusted so your feet rest flat on the floor. If your chair has arms, they should be adjusted to provide arm support while you are typing. Your wrists shouldn't rest on the keyboard when typing.
- Rest breaks - To prevent eyestrain, try to rest your eyes when using the computer for long periods. Rest your eyes for 15 minutes after two hours of continuous computer use. Also, for every 20 minutes of computer viewing, look into the distance for 20 seconds to allow your eyes a chance to refocus.
- Blinking - To minimize your chances of developing dry eye when using a computer, make an effort to blink frequently. Blinking keeps the front surface of your eye moist.
Regular eye examinations and proper viewing habits can help to prevent or reduce the development of the symptoms associated with Computer Vision Syndrome.
Also, from WebMD:
- Tweak your computer settings. You don't have to live with the factory-installed settings on your computer if you're uncomfortable. Adjust the brightness, contrast, and font size until you find the best settings for your vision.
Gunnar glasses: Studies have shown some short term relief but generally no evidence has yet surfaced to support benefits of these glasses for long term health.
The Vision Council, which represents the manufacturers and suppliers of the optical industry, suggests the following tips to prevent and lessen digital eye strain:
Also check the following image as a guidance: