Blue light is the current nemesis of the vision world, as its been shown to be able to damage retinal cells in the eye, and mess up sleep rhythm in people who read on their iPhones before bed.  A quick Google search show a substantial number of articles and medical journals validating this claim.  First, a quick background on how we got to this point:

The world around us is made up of all kinds of light waves, ranging from the visible light (you know ROY-G-BIV*, the rainbow colours), to the non-visible light (such as ultraviolet and infrared).  It has become pretty common knowledge, especially in the last decade, that all UV light is harmful (yes, that includes UVA,  even though tanning-bed 'truthers' may disagree).  In fact, we take great steps to block UV light, like wearing hats and applying sunscreens, and when it comes to the eyes, more and more people are wearing sunglasses when outdoors (and indoors, for reasons I cant explain).  Protecting against UV light is pretty wise, as UV exposure has been linked with skin cancer, cataracts, and other eye pathology.   However, it turns out that the majority of UV light can't penetrate all that deep into the eye, so the majority of eye diseases linked to UV exposure are limited to the front half of the eye.  What can penetrate deep into the eye is the visible spectrum of light (ROY-G-BIV).   When you realize ROY-G-BIV is arranged in order from weakest energy light (ROY) to highest energy (G-BIV), and if you include UV, the list now becomes ROY-G-BIV-UV, it is plain to see that Blue, Indigo, and Violet are the direct cousins of UV light, and pack a decent punch (they therefore are termed High Energy Visible light, HEV).  This becomes concerning since these colours have the ability to penetrate all the way into the eye and we do very little to try and stop it. Sunlight, LED lights, digital devices, and TV screens all emit a significant portion of blue light, and we are exposed to these sources for hours each day, especially when watching a four hour long ballgame.  A study by the Paris Vision Institute determined the exact range of blue light that is most harmful to our retina cells and made suggestions on how to block this wavelength.  This has led to the major lens manufacturers creating a coating on their lenses which can selectively block and reflect this particular band of harmful light while allowing the other beneficial bands of light to pass into eyes (particularly the blue-turquoise band which our body uses to set our internal circadian clock).  

So, does that mean parking yourself in front of your 60" TV screen for 4 hours and watching the Blue Jays can be harmful to your eyes?  Likely no, and certainly no more hazardous than watching any other TV show for 4 hours.  Studies are still sparse on how much blue light one receives from a screen, even after a full day of exposure.  It seems, though, that our monitors and phones emit such low intensity of light, that even after a full day of computer use our total blue light exposure is of a similar quantity as one would get from only a few minutes of direct sunlight exposure.  And any increase from watching a screen that has predominantly blue images is almost assuredly negligible when compared to average screen viewing.

It still probably a good idea to at least consider getting a blue blocking coating (Nikon SeeCoat Blue, Hoya Recharge, or Essilor Crizal Prevencia) on your next pair of glasses if you have a family history of age-related macular degeneration, or have significant exposure to sunlight, computer screens or LED lights .   But you can be reassured that you can continue to watch the Jays without worrying about doing additional damage to your eyes.  And that's a good thing, because the Red Sox really don't need any more reasons to attract bandwaggon fans.

* Red Orange Yellow Green Blue Indigo Violet

Dr. Burke is an optometrist practicing at Calgary Vision Centre.  Opinions above do not constitute medical advice, and readers should consult with their optometrist if they have questions or concerns about their eye health.