Blue Blocking Glasses
Recently there has been a lot of public interest in blue blocking lenses. I have had many patients ask for my opinion about them. There are three frequently asked questions surrounding blue light:
What is the cumulative effect on the retina over time from blue light and the potential effect on eye health?
What is the effect of blue light on our “biological clock”?
Does blue light cause eyestrain?
The truth is that we don’t know the definitive answer to these questions partially because not enough research has been done and the effects can be variable depending on the chemistry of the individual’s retina.
Blue Light & Retinal Health
Question one relates to the effect of blue light on retinal health. I have heard retinal experts argue on both sides of this issue. Some feel that not enough energy reaches the retina to cause damage, while others feel that the effects on the retina can be profound especially with individuals with lower concentrations of macular pigments. Macular pigments make up a layer in the retina that is responsible for protecting the rods and cones in our eyes. The retina is a very active tissue. As a byproduct of the metabolic activity, waste products are produced by retinal cells. These waste products must be removed otherwise they will accumulate leading to disorders such as macular degeneration. It turns out that not everyone possesses the same ability to protect these vital structures in the retina. Some have greater levels of Lutein and Zeaxanthin in the retina than others. It is possible that those individuals with lower amounts of these substances may be more susceptible to the effects of blue light than others. The fact that adults are exposed to hours of exposure to blue light from electronic devices is therefore potentially worrisome. That concern is even greater for the generations who are starting with this exposure at much younger ages. Perhaps as our devices evolve, this issue will be addressed lessening the burden of blue light.
Blue Light & Our Biological Clock
Question two relates to the effects of blue light on our biological clock or Circadian Rhythms. It is accepted that blue light affects our wake/sleep cycle. If our exposure to blue light comes too close to when we should be sleeping, this can affect the quality of our sleep and the effects on our health can be significant. Many devices can be programmed to dim the light source at a chosen time to aid in this problem.
Blue Light & Eye Strain
Question three asks about blue light causing eyestrain. Eyestrain is a function of many variables that come into play while we are engaged with electronic devices and is more likely to be caused by the root of the eyestrain rather than the blue light itself. These variables include:
How close the device is to our eyes (how much focusing demand we are placing on our eyes)?
How much focusing ability we have to deal with under that demand?
How capable is our muscle system of converging our eyes on that target for that amount of time?
How often do we blink?
Is there a history of or susceptibility to dry eye?
If our focusing system or converging system is on the weaker side, we have a greater propensity to eyestrain. People who do have strong focusing and converging systems can experience eyestrain by working too long at the near point.
Our philosophy is to recommend specific visual correction to those who have a job with a high demand for near work. My prescription will include lenses that take focusing stress off the eyes and may also include prism to relieve the amount of demand on the converging muscles as well. It is frequently beneficial to use an anti-glare coating on the lenses. For those who may be concerned or susceptible blue light damage, we may incorporate a blue blocking lens. At this point, we have not seen enough important evidence to suggest that everyone needs to purchase a blue light filter. It is important that people discuss that with an eye-care professional before succumbing to an internet ad for cheap filters as you may be short changing yourself of better options. remember, you get what you pay for.
- Dr. Kevin B. Wynne