The Myopia Pandemic

Aug. 28, 2015

By Medical Discovery News

The Myopia Pandemic

You’ve probably heard of pandemics – the plague, influenza, HIV – but you might not have seen coverage of the growing myopia pandemic. Before you consider bathing in sanitizer, you should know that myopia isn’t contagious. Another word for it is nearsightedness.

Myopia is a condition in which close objects are seen clearly but distant objects are blurred due to the elongation of the eye or too much curvature of the cornea. This causes light entering the eye focusing in front of the retina rather than on it. Myopia is different than hyperopia, which is the kind of nearsightedness that comes from growing older. In fact, the myopia pandemic is primarily affecting young people.

It currently affects 90 percent of the young adults in China, although 60 years ago it was 10-20 percent. In the United States and Europe it affects about half of all young adults, double what it was 50 years ago. Seoul has the highest incidence: 96.5 percent of young people in South Korea’s capital have myopia. An estimated 2.5 billion people will experience myopia by 2020.

Vision issues can be corrected with glasses, contact lenses, or surgery, but none of those fix the underlying defect. Eye elongation can stretch and thin parts of the inner eye, which can increase the risk of retinal detachment, glaucoma, cataracts, and even blindness.

Genetic causes have been discounted, so this rapid change has to come from something in the environment. More than 400 years ago, Johannes Kepler, an astronomer and expert in optics, wrote that his intense studying led to nearsightedness. Today, students are not only studying a great deal but are also spending much of their time with cell phones, tablets, computers, and video games, primarily indoors.

Intense periods of reading and studying were disproved as a cause of myopia during a study in 2000. Seven years later, scientists from Ohio State University followed more than 500 eight- and nine-year-olds with healthy vision and tracked the time they spent outdoors. After five years, 20 percent had developed myopia, which correlated to the time they spent indoors. This was confirmed one year later, when scientists in Australia studied 4,000 students and also reported that the amount of time spent indoors was the important factor.

It’s probably because the retina of the eye produces and releases more dopamine, a neurotransmitter, during the day to signal the eye to switch from night to daytime vision. Indoor light disrupts this cycle, affecting eye development. Only 30 percent of Australian children who spent three or more hours outside each day had myopia. A systematic review paper aggregated previous studies and concluded that each hour of each week spent outside reduces a child’s chance of developing myopia by 2 percent.

Researchers are examining possible ways to control the development of myopia, such as altering the way contact lenses focus light, producing eye drops that block neurotransmitter release, and using artificial lights like those used to treat seasonal affective disorder, also known as winter depression. Of course, having children play or simply be outside seems the best option, and it has other health benefits too.

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Statins Can Save Your Eyes

May 10, 2013

By Medical Discovery News

Today, 2.7 million Americans over the age of 40 are suffering from an eye disease that slowly robs them of their sight. And about half of them don’t even know they have it, despite the fact that a comprehensive eye exam will easily detect it. While there is still no cure for glaucoma, a new study shows that statins, one of the most commonly used class of drugs, might actually prevent it.

Glaucoma usually occurs when the pressure of the fluid in the eye slowly increases, eventually damaging the optic nerve. The optic nerve is actually a bundle of nerves that carries information from the eye’s retina to the brain, where images are interpreted. The fluid in the eye, called the aqueous humor, circulates around inside the eye. This fluid provides nourishment to parts of the eye that do not have blood vessels and maintains the appropriate pressure inside the eye, both of which are keys to normal vision. A small amount of the fluid is produced every day while an equal amount flows out. With glaucoma, the fluid does not leave the eye as it should, gradually increasing the pressure on the eye as fluid accumulates.

A nationwide study by the University of Michigan School of Medicine found that statins like Lipitor and Zocor can lower the risk of developing glaucoma. The largest study ever done on this topic followed 300,000 people aged 60 and over who were diagnosed with hyperlipidemia, or high levels of unhealthy fats called lipids. In taking statins continuously for two years, the subjects reduced their risk of developing the most common kind of glaucoma by almost 10 percent.

The most common type of glaucoma, called primary open-angle glaucoma, is caused by not enough of the fluid draining. Other types of glaucoma can be caused by the iris blocking the eye’s fluid from draining, inheriting genes for the disease, injury to the eye, tumors, or even steroids. Treatment for glaucoma depends on the type of glaucoma, its severity, and its response to treatment. Medicated eye drops can either increase the drainage of the fluid or reduce its production. Several types of surgery and laser treatments can improve the fluid drainage. Medical marijuana can reduce pressure on the eye, but only for a short time and is not a recommended treatment. 

For the millions of the people already taking statins, the study revealed a surprising added benefit. Leaders of the study do not yet know why statins have this effect, but think it may be due to the drug increasing blood flow to the optic nerve and retinal nerve cells and pushing out extra fluid, alleviating pressure in the eye.

Annual eye exams are a good addition to a yearly physical, especially for those most at risk for glaucoma: blacks, Hispanics, seniors, those with diabetes, and those with a family history. The damage caused by glaucoma is irreversible, so prevention and early detection are currently the best way to combat the disease.

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