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Eye Strain from Computer Use & Reading
Allie wrote:
If you are experiencing eye strain, from computer use and reading, should you remove your contacts and put on your glasses? (I don't enjoy wearing my glasses, and prefer my contacts, but if wearing my glasses will help with the eye strain, then I will switch). Thanks
Dr Carol Doman's response:
Allie,
I cannot answer this question for you specifically without knowing your exact situation. I would definitely recommend making an appointment to see your optometrist to find out the cause of your eye strain and what the best treatment would be for you.. There are a number of reasons why glasses are sometimes better for computer use versus contact lenses. When on the computer specifically we blink 50% less than during other activities and as a result dry eye increases. This increase in dryness can be more noticeable with contact lenses than with glasses. Depending on a person’s age the focusing with contact lenses and glasses can be different. People who have myopia (near-sightedness) and are over 40 will start to experience increased strain and problems focusing on things up close (computer and print). These symptoms will be worse with contact lenses because you have to use more effort to focus on things up close compared to glasses. If you are over 40 ask your optometrist about multifocal contact lenses, which give better near vision. Anyone spending prolonged amount of time on a computer are advised to follow the 20-20-20 rule. Every 20 minutes they should take a 20 second break and look 20 feet away.
Dr. Doman
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Eye Strain and Non-Prescription Computer Glasses
Violette wrote:
I use the computer a lot, whether it is for gaming, surfing the web or doing homework. Occasionally, my eyes will feel tired and get bloodshot, and I'll even get a headache. Recently, I heard of non-prescriptive computer glasses (the brand is Gunnar Optiks), and I was wondering whether or not I should buy a pair. I would rather not get prescriptive computer glasses because as I don't want to get dizzy each time I focus on something else. Furthermore, I was wondering what would be optimal settings on a computer to prevent eye strain. Thank you!
Dr Henry Smit's response:
Dear Violette
If you are experiencing eye fatigue and headaches when you use the computer, you may have an uncorrected refractive error – that is, you might be somewhat farsighted or nearsighted, or you may have some astigmatism. All of these conditions can contribute to the symptoms you describe, and can all be corrected with a pair of prescription eye glasses. The GUNNAR glasses you are considering would not correct any of these conditions. Your bloodshot eyes may be an indication that your eyes are becoming dry. This occurs frequently because, as a number of studies have shown, our blink rate decreases with periods of intense computer use.
There appears to be a lot of self generated hype and marketing around the GUNNAR eyewear products, but it seems to me that the hype outweighs the science. The lenses have a slight amber tint which will give an appearance of enhanced contrast and that might be somewhat more comfortable for some viewers. They are also touted as creating a moist microclimate between the back surface of the lens and the front of the eye – this is claimed to help keep the eyes more moist. As to this claim, they are not likely to be any more effective than regular prescription glasses.
I think your first step should be to have a thorough eye examination from your optometrist to determine if there are underlying issues such as uncorrected refractive error or dry eye syndrome. Treating these conditions, if they exist, can make you more comfortable at the computer.
As for how to best set up your computer, I recommend that you visit the CAO web-site for additional information. There is an excellent article at http://opto.ca/en/eye-health-info/eye-health-library/vision-computers.html that I am sure you will find informative.
Hope this is helpful,
Dr. Smit
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Re: Best Font Size for Comfortable Reading
Ernie wrote:
My friends and I are getting a little on in years (middle-age) and finding that some of the labels on some products are getting so small, nothing short of a magnifying glass can read the material. Some of these products are for cooking instructions, prescriptions and other important day to day needs. The font sizes are 3 or 4 or 5 and getting hard to make out without help. If our favourite optometrist is adjusting our eyesight for 20/20, what is the most common, comfortable size font that we should be able to read.
On a side note and maybe related, what is the best foreground, background colour for printed material to make it legible? Thanks for any information.
Dr Langis Michaud's response:
Dear Ernie Your question is a good one. In theory, a human eye can see 20/10. That means that a person can see at 20 feet what an average other person could see at 10 feet…. In another way: twice better the normal vision. However, this level is almost never reached because of many, many elements in our visual system. The eye is a complex organ and anything that can disturb the passage of a ray of light through the ocular environment will degrade this capacity to see clearly. For example, a cataract will have a significant impact on the clarity of things seen and the capacity to see for the affected individuals. Very early in the aging process, by age 45 and older, our natural lens, inside of the eye, begins to lose some transparency, and has a limited capacity to make focus at near. This degrades the capability to see small prints as you describe. On average, a font of 8 to 10 could be easily seen if your eyes are healthy, your retina in a perfect shape and your prescription well adapted to your condition. Lighting is an important factor. In a reduced illumination, contrast can be hard to be seen by the human eye: our best cells (cones) to see acts 80% of the time on a regular or higher lighting condition. When darkness comes or under a reduced illumination environment, we rely on cells (rods) that are much less effectives that our cones. This limits also the capacity to see small print. Best vision is provided with sharp contrasts: black on a white background or vice-versa. If you have a job or a hobby that necessitates high resolution vision, consult your optometrist and he will be able to determine glasses for these specific needs. For example, I have jewellers with very precise visual demands…. I fitted them with magnifying reading glasses and they can see every detail they want. However, these glasses are not suitable for a day-to-day task such as for reading a newspaper. They are adapted and have to be worn under specific circumstances. Your optometrist will also be able to give you recommendations on the lighting, on the way to adapt your environment to ease your reading or visual tasks. Good luck, Dr. Langis Michaud
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