Blue Light Blocking Glasses: Do They Really Work? - Ophthalmology

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Hello Sabina,
Thank you for your inquiry regarding blue light blocking glasses and their effectiveness. It's great to see that you are taking steps to protect your eye health, especially in our increasingly digital world where exposure to blue light is prevalent.

To address your first question about the cumulative effect of blue light filtering: if your new blue light blocking glasses filter out 70% of blue light and your existing prescription glasses filter out 20%, it does not simply add up to a total of 90% filtering. The filtering percentages are not additive in a linear fashion because they are based on the light that passes through each lens. Instead, the total amount of blue light that reaches your eyes will depend on how much light is filtered by each lens in conjunction with one another. Therefore, while wearing both glasses may provide a higher level of protection than wearing just one pair, it is not accurate to say that you are filtering out 90% of blue light.

Regarding the appearance of faint blue halos or circles when wearing both pairs of glasses, this phenomenon can occur due to reflections and refractions of light between the two lenses. When light from sources like LED ceiling lights hits the lenses, it can create reflections that may appear as blue circles or halos. This is generally not harmful to your eyes, but it can be distracting. If you find this effect bothersome, you might consider wearing only one pair of glasses at a time, or ensuring that the lenses are clean and free from smudges, which can exacerbate reflections.

As for the potential harm of blue light, current research indicates that while blue light exposure from screens and LED lighting can contribute to digital eye strain, there is no conclusive evidence that it causes permanent damage to the retina or leads to conditions such as macular degeneration. However, it is still advisable to practice good eye hygiene, such as taking regular breaks from screens (the 20-20-20 rule: every 20 minutes, look at something 20 feet away for 20 seconds), ensuring proper lighting when reading or working, and maintaining a comfortable distance from screens.

In summary, while blue light blocking glasses can help reduce exposure to blue light, their effectiveness can vary based on the specific lenses and coatings used. The appearance of blue halos is likely a result of light reflection and is not harmful. If you have ongoing concerns about your eye health or the effects of blue light, it would be beneficial to consult with an eye care professional who can provide personalized advice and recommendations based on your specific situation.

Wishing you a happy and healthy new year!
Best regards.