Will blue light from electronic devices increase my risk of macular degeneration and blindness?

Originally Posted Here: https://www.health.harvard.edu/blog/will-blue-light-from-electronic-devices-increase-my-risk-of-macular-degeneration-and-blindness-2019040816365

Every day, retinal specialists are asked about the risks from blue light emitted from electronic devices. (Retinal specialists treat conditions affecting the retina, a thin tissue at the back of the eye that is responsible for vision.) Many people ask whether blue light will increase their risk of age-related macular degeneration and blindness.

The short answer to this common question is no. The amount of blue light from electronic devices, including smartphones, tablets, LCD TVs, and laptop computers, is not harmful to the retina or any other part of the eye.

What is blue light?

Blue light is visible light between 400 and 450 nanometers (nm) in frequency on the visible light spectrum. As the name suggests, this type of light is perceived as blue in color. However, blue light may be present even when light is perceived as white or another color.

Blue light is of concern because it has more energy per photon of light than other colors in the visible spectrum, i.e. green or red light. Blue light, at high enough doses, is therefore more likely to cause damage when absorbed by various cells in our body.

How do we perceive color?

Our perception of color relies primarily on four main light-sensitive cells: three cone photoreceptors and one rod photoreceptor. These cells reside within the retina.

During the daytime, the three cone photoreceptors actively sense light, and each has a peak sensitivity in either the blue, green, or red portions of the visible light spectrum. On the most basic level, our sense of color is determined by the balance of activity of these three cells. When the light is too dim to stimulate the cones, our sense of color is extinguished. We perceive the world in shades of gray because only one type of photoreceptor, the rod, is maintaining our visual function.

LED technology and blue light

Most incandescent light sources, like sunlight, have a broad spectrum of light. However, light emitting diodes (LEDs) produce relatively narrow peaks of light that are crafted by the manufacturer. This allows light from LEDs to be perceived as almost indistinguishable from white light, or daylight. (They can also be made to mimic traditional artificial light sources.)

White LEDs may actually emit more blue light than traditional light sources, even though the blue light might not be perceived by the user. This blue light is unlikely to pose a physical hazard to the retina. But it may stimulate the circadian clock (your internal biological clock) more than traditional light sources, keeping you awake, disrupting sleep, or having other effects on your circadian rhythm.

The screens of modern electronic devices rely on LED technology. Typical screens have individually controlled red, green, and blue LEDs tightly packed together in a full-color device. However, it is the bright white-light LEDs, which backlight the displays in smartphones, tablets, and laptop computers, that produce the greatest amount of blue light.

Risks from blue light

It all comes down to this: consumer electronics are not harmful to the retina because of the amount of light emitted. For example, recent iPhones have a maximum brightness of around 625 candelas per square meter (cd/m2). Brighter still, many retail stores have an ambient illumination twice as great. However, these sources pale in comparison to the sun, which yields an ambient illumination more than 10 times greater!

High-intensity blue light from any source is potentially hazardous to the eye. Industry sources of blue light are purposely filtered or shielded to protect users. However, it may be harmful to look directly at many high-power consumer LEDs simply because they are very bright. These include “military grade” flashlights and other handheld lights.

Furthermore, although an LED bulb and an incandescent lamp might both be rated at the same brightness, the light energy from the LED might come from a source the size of the head of a pin compared to the significantly larger surface of the incandescent source. Looking directly at the point of the LED is dangerous for the very same reason it is unwise to look directly at the sun in the sky.

Compared to the risk from aging, smoking, cardiovascular disease, high blood pressure, and being overweight, exposure to typical levels of blue light from consumer electronics is negligible in terms of increased risk of macular degeneration or blindness. Furthermore, the current evidence does not support the use of blue light-blocking lenses to protect the health of the retina, and advertisers have even been fined for misleading claims about these types of lenses.

The bottom line

Blue light from electronic devices is not going to increase the risk of macular degeneration or harm any other part of the eye. However, the use of these devices may disrupt sleep or disturb other aspects of your health or circadian rhythm. If you are one of the large number of people who fall into this category, talk to your doctor and take steps to limit your use of devices at night, when blue light is most likely to impact your biological clock.

The post Will blue light from electronic devices increase my risk of macular degeneration and blindness? appeared first on Harvard Health Blog.


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Lead exposure and heart disease

Originally Posted Here: https://www.health.harvard.edu/blog/lead-exposure-and-heart-disease-2019040516296

When we think about the health effects of lead contamination, the biggest worry is for babies and young children. Lead, a heavy metal that is widespread in the environment, can harm developing brains. But growing evidence suggests that low levels of lead in the blood may also raise the risk of heart disease in adults.

Last year, a study in Lancet Public Health found a link between lead exposure and a higher risk of death from cardiovascular disease. The data came from more than 14,000 people in the United States who were adults in the late 1980s. The association persisted after researchers controlled for many confounding factors, and was evident even among people with blood lead levels of less than 5 micrograms per deciliter (µg/dL). Until 2013, only levels higher than 10 µg/dL were considered worrisome, and mainly for children.

Lead’s legacy

“Today, average blood lead levels are just over 1 µg/dL, down from an average of 10 µg/dL in the 1980s,” says Dr. Rose Goldman, associate professor of medicine at Harvard Medical School. But there is no safe blood level of lead, according to the Centers for Disease Control and Prevention. And even though the body eliminates about half of the blood lead in the urine after one to two months, a portion of it goes into the bones, where it can stay for decades, she says. Bone tissue constantly remodels itself, and that stored lead can be released back into the bloodstream in response to different conditions, including pregnancy, breastfeeding, hyperthyroidism, and aging.

Although deaths from cardiovascular disease dropped by 43% between the mid-1980s and the early 2000s, improvements in traditional risk factors, such as cholesterol and blood pressure, cannot fully account for that decrease. According to a 2017 study in the International Journal of Epidemiology, nearly one-third of the drop over that time period may be explained by the reductions in exposure to lead and cadmium, another heavy metal. Those reductions are the result of public health policies such as smoking bans, air pollution improvements, hazardous waste cleanups, renovations in drinking water infrastructures, and the ban on lead in gasoline.

Get the lead out

Despite those successes, lead remains an insidious presence in daily life. Because even low levels of lead can be dangerous, people should take steps to minimize their lead exposure throughout life, says Dr. Goldman.

Lead paint is still found in buildings and steel bridges constructed before 1978. Following natural disasters such as hurricanes, lead from these structures can enter the environment and raise soil lead levels. Amateur home renovators who scrape and sand old painted surfaces can inhale lead dust. Don’t risk the DIY approach; hire an EPA-certified lead abatement professional. Lead can also contaminate drinking water due to erosion from lead pipes, mainly in homes built before 1986. Consider testing your water, especially if young children live in your home.

Other possible sources of lead exposure include:

The FDA’s recommended limit for lead in lipstick (which may be ingested when a woman licks her lips) is 10 parts per billion, but some brands contain much higher amounts. Consider seeking out lead-free brands. In October 2018, the FDA banned lead acetate from hair coloring products. But companies still have a year to comply with the ruling, so check labels if you use these products, which are mainly drugstore brands that gradually cover gray. Indoor and outdoor firing ranges can expose people to dust from lead bullets. Wild game shot with leaded bullets may also be contaminated with lead. Both Ayurvedic remedies (an alternative form of medicine from India) and traditional Chinese medicinal herbs may be contaminated with lead, as evidenced by high blood levels seen in some users. Cooking or eating off lead-glazed ceramics (usually decorative traditional pottery, not commercially made products) has caused lead poisoning. Hardware stores carry lead testing kits you can use to check such products.

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Discontinuation syndrome and antidepressants

Originally Posted Here: https://www.health.harvard.edu/blog/discontinuation-syndrome-and-antidepressants-2019040416361

Discontinuation and change are part of life. We all start and stop various activities. Jobs change, relationships change. So, too, may medical treatments, such as antidepressants that help many people navigate depression and anxiety. Planning changes in advance tends to make things easier and smoother. You may start a medication for treatment and discover that it’s not helping your particular medical issue. Or perhaps you’re having side effects. Or maybe your condition has improved, and you no longer need the drug. If so, working with your doctor to change or stop taking an antidepressant slowly may help you avoid uncomfortable symptoms known as discontinuation syndrome.

What is discontinuation syndrome?

Discontinuation syndrome can be a consequence of stopping certain types of antidepressants: selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs). You may have heard about this from a friend or on the news, or perhaps read a recent New York Times article on this topic. If you are taking an antidepressant, you may be concerned about your own response to stopping the medication.

Let’s clarify what the term means. Discontinuation syndrome describes a range of symptoms that may occur in patients taking SSRIs or SNRIs after stopping quickly. These can include:

nausea feelings of vertigo trouble sleeping odd sensory symptoms, such as “pinging” feelings in the skin, or what some people describe as a “zapping” sensation in the brain feeling anxious.

As many as one in five people who stop an antidepressant quickly may experience at least a mild version of these symptoms. Usually discontinuation syndrome occurs when a person has been taking medication for at least six weeks or longer. And it’s more likely to happen if you have been taking medication for a long time.

When people stop taking medication, some antidepressants leave the body quickly (short half-life), while others leave the body more slowly (long half-life). Discontinuation symptoms may occur in either case, especially if a drug is stopped abruptly.

Symptoms usually start two to four days after stopping the medicine. They usually go away after four to six weeks. In rare cases, they may last as long as a year.

What are SSRIs and SNRIs?

An SSRI is a type of antidepressant. Examples include fluoxetine (Prozac), paroxetine (Paxil), and sertraline (Zoloft). These drugs make a neurotransmitter called serotonin more available in the brain. Experts believe this helps reduce symptoms of depression and anxiety and regulate mood.

SNRIs are another type of antidepressant. Examples include duloxetine (Cymbalta) and venlafaxine (Effexor). These drugs work on two neurotransmitters: serotonin and norepinephrine.

These two classes of antidepressants are groundbreaking. Older antidepressants had many hard-to-tolerate side effects, including severe fatigue, dry mouth and eyes, and difficulty urinating. In contrast, SSRIs and SNRIs are generally well tolerated. Like all drugs, though, they do have side effects, including effects on sexual function, which can be difficult to talk about, but are important to tell your physician. Each drug is a little different, and an experienced psychiatrist can help people choose the best option for them.

We encourage patients to think broadly about treating depression. Treating depression with medicine can be very effective. Talk therapy, including cognitive behavioral therapy, also has been shown to be very helpful, as have exercise and social activities. Think about treatment for depression like a menu at a restaurant where you can choose foods from more than one column. Often, a combination of medicine and nondrug treatment maximizes the benefit of both.

What if you’re ready to stop taking an antidepressant?

Let’s suppose you have been on an SSRI like paroxetine for several years and having been working with a psychologist whom you really trust. Your depression is better and you feel ready to stop your medicine. To help you avoid discontinuation syndrome, work closely with the doctor who prescribes your medicine.

While some drugs can either be stopped or very quickly tapered, almost all SSRIs and SNRIs need to be slowly decreased. You may be instructed to drop the dose by small amounts each week, or perhaps every two weeks, or even every month. If you’ve been on a higher dose of medication, a taper may take as long as six months. It’s not worth rushing it because you don’t want to develop discontinuation symptoms. However, if you do, your doctor can increase the dose and then after a little while, you can try the taper again.

We have had patients tell us that physicians don’t want to start these antidepressants for fear of triggering discontinuation syndrome when it’s time to stop taking the medicine. But these are useful and safe medications for most people, and it’s worth exploring their potential carefully. Depression is a serious and common affliction that should be actively treated by all effective methods.

Christopher Bullock, MD, MFA, 1947–2018, was a psychiatrist, psychoanalyst, and writer. He loved Gary Snyder’s poetry; “all the junk that goes with being human” was a quote that inspired his life, his work, and his illness.

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