Computer-related eyestrain – The 20/20/20 Rule

Leave a Comment

Everybody’s doing it – using screens, I mean.  Smartphones, computer monitors, laptops, tablets – you can hardly avoid using at least one of them, even if you wanted to. With COVID-related changes in schooling and working from home, screen use is way up for many of us,  and so is device-related eyestrain.  What to do?

First off is to use the 20/20/20 Rule.  Every 20 minutes, look away from your device.  Look at something 20 feet (or 6 metres) away, for at least 20 seconds.  Simple, huh?  While remarkably resilient, your eyes and visual system can tire, and then you may experience strain, headache, blurring, and other unwanted effects.  Giving your eyes a break frequently can help reduce these effects.  I am fond of saying that you can only stand on one leg for so long before you tire (unless you’re a flamingo), but if you take a rest every so often, you can do it for a much longer time.

Another fact of screen use is that we blink our eyes much less frequently when we are concentrating on something; your blink rate can be a little as 1/4 of what is normal. The end result is that the eye surface will begin to suffer from exposure  because it’s not being refreshed often enough, and then you get redness, dryness, stinging and burning.  The 20/20/20 rule helps here as well, but you may also benefit from using a lubricant eye drop the add some moisture to the eye surface.  Products that claim to remove the redness are not advised; they’re like nasal spray for your eyes, and can cause your symptoms to actually get worse down the road.  Stick with proper artificial tears, like Systane, Blink, ReFresh, or Hydrasense.

All of the above advice is given with the assumption that you have good vision and up-to-date eyeglasses, if needed.  If you haven’t had an eye exam in a while, that would be a good first step.


Blue light filters and LCD screens – the truth behind the hype.

Leave a Comment

There’s a lot of media attention and advertising time being devoted to the possible harmful effects of blue light, specifically the blue light emitted from LCD screens such as phones, tablets and computers.  The dangers suggested range from eyestrain to eye health damage such as cataracts and macular degeneration.  So how much of a risk is there?

The short answer is:  none.  That’s right, no risk of eye damage from your phone, etc.  Blue light is not inherently harmful to  our eyes; if it was, we’d all be blind just from exposure to the sky!  Also, the intensity of the light from a screen is miniscule, compared to the everyday brightness of just being outdoors.

This all started with a study ( published in 2018 by a cellular biochemist doing research at the University of Toledo.  Essentially, they bought commercially-available human cells (cervical cancer cells, actually), and then genetically engineered these cells so they produced a light -sensitive molecule that is normally only found in the eye’s light receptor cells. They shone blue light on this concoction in a glass dish to activate the light-sensitive molecule, and watched what happened.  They found that the activated molecule interfered with other molecules in the cell, and eventually the cells died.  Interesting, but nothing like what actually happens inside the light receptor cells in your eye.  Not even close.  A newspaper at the U of Toledo published a story on this research, a story which was full of erroneous leaps of “reasoning”; the paper USA Today picked up on the UT article, and BOOM – a health “crisis” was born.  Clever marketing types at eyeglass lens companies picked up on this, and quickly developed products to protect the public from this new health threat.

It’s all marketing hype, and it’s making some people richer while providing nothing of value to you, the patient.  I will admit that some patients feel that these special lenses help with their strain and fatigue, and I accept that, because hey, we don’t know everything.  But don’t buy into the scare factor that says if you don’t use our blue light filters, you could lose your vision!

So no, blue light from your cellphone is NOT going to make you blind.

see also

Should You Order Your Glasses Online?

Leave a Comment

Ordering your new glasses online can seem like an inexpensive way to buy eyewear, but be advised that there are a number of shortcomings to this approach.  Firstly, prescription frames are kind of like clothing or shoes:  until you try them on, you don’t know how they’ll fit or feel.  And because they arrive by mail in a box, you’ll have no one to adjust them for you if they’re not right.    ♦At our office we will advise you on the fit of your frames so you make a good choice, and adjust them for you when you pick them up.  Second, the colour or finish may look different in person than in a web page picture.     ♦We’re always happy to order a frame in other colours so you  can see it in person.  Third, you have no way of knowing if the lab has filled the prescription accurately;  recently a patient of mine came in for an annual checkup with glasses she’d bought online the year before.  Interestingly, they didn’t match the prescription I had given her and her vision was not a clear as it should have been.  Someone had either deliberately changed her ‘script, or they made a mistake and didn’t catch it (or care).     ♦We check each completed job ourselves when they come back from the lab to make sure they’re done right.  And finally, what if something just doesn’t seem right with your new glasses?  Who will be able to help you?  The help desk at the e-store?   Not likely.  The optometrist who did your eye exam?  Not unless you pay for them to assess the issue.    ♦When you purchase your glasses from us, we’re here to help if you have any concerns or problems with your new eyewear.

One final note:  Ontario law requires that eyeglasses be dispensed by a licensed, qualified person to make sure things are done properly; online retailers are actually breaking Ontario law by selling you glasses by mail.

Children’s Vision Care

Leave a Comment

We care about children’s vision!  All children should have their first eye examination by the age of 3, or earlier if you or your family doctor has any concerns.  Testing can detect conditions that may lead to what is called amblyopia, or “lazy eye”, in which the vision in one eye does not develop properly..  However, if a diagnosis is made early, then steps can be taken to correct the eye problem and strengthen this vision in the weak eye.  Once a shild is over the age of 7 or 8, it may be too late and the poor vision will be permanent.  As your child grows, more and more of their learning comes through vision, up to 80% in fact.  A child who sees poorly may not perform well in school, or they may get frustrated and have what seems to be behavioural issues.  Tests at the family doctor’s office or in-school screenings are not enough to properly assess your child’s vision.   Contact us to set up an appointment for your child(ren) today.