While taking rest breaks is required, if you wear glasses, wearing computer glasses is one of the best things you can do to relieve eye strain while using a computer.

Standard bifocals and progressive lenses are not nearly as useful for relieving computer eye strain.  Progressive lenses may have an area of the lens that works well with the computer, but it is very small area and not nearly as comfortable as computer glasses.

Single vision computer glasses are an excellent way to go and the least expensive.  You may have to swap between eyeglasses during the day, but it is worth the trouble.

It is preferable to have an Rx for computer glasses.

Important – Make certain your vision Rx includes the pupillary distance (PD).

The best way to obtain a prescription for computer glasses is from your eye doctor or optometrist.  Ask him/her during your regular eye exam.

Or measure exactly how far your computer screen is from your eyes, call your eye doctor or optometrist and give him that distance.   He can then write a prescription for computer glasses.

If for some reason that is not feasible or too expensive, here are some alternatives.

If you wear prescription glasses that are not computer glasses, take them to an optical store and ask them to check the lenses and write down the Rx for them.  Most optical shops have a machine that can read the Rx from your lenses.

If that option is not available to you, then print this special eye chart to find the strength of inexpensive reading glasses to use with your computer: http://www.computervisionreadingeyeglasses.com/computer_chart.htm

Using the eye chart, you can then purchase inexpensive pre-made reading glasses over the Internet or at a local drug store.  (However, this is not a very good option if you already wear prescription glasses for reading or distance.)

If you have your regular vision Rx,  calculate a more precise computer Rx than the eye chart method using your regular eyeglasses prescription as follows according to Zenni Optical:

‘Single vision computer glasses – Split the Add number in half, and combine that split number with the Sph. Discard the remaining Add, and leave the Add data entry field blank. Enter the Cyl and Axis values for both eyes. These values are not changed in any way. Use the distance PD.’  You may want to visit Zenni for more explanation of the terms.

Once you have an Rx for computer glasses, you can then order computer glasses online from a discount provider like Zenni Optical made to your Rx for as little as $15 or less including lenses and frame.  If cost is not a concern, you can order them at a walk-in retail optical store and the retailer can also help with adjusting the frames for the best fit.  And you can try the frames on before you buy.

Or use these tips summarized from Ehow.com:

Go to a local pharmacy and select a pair of reading glasses that matches your computer RX.  Pharmacies typically have a display of several different glasses of varied strengths.

Try on a few pairs of glasses at the pharmacy display. If you measured your computer screen to be approximately 21 inches from where you sit, which is the general distance of most computers, then this is also the approximate length of your arm.  Stand an arms length away from the reading chart provided by the glasses display and see if you can read print the approximate size of the text on your computer screen.

Fine-tune your glasses strength. If you feel it is not quite right, try going up or down with the power of the glasses by a quarter step (+/- 0.25) to see if you can find that perfect balance.