Excerpts from science, technology, environment and health reports from around the web.

When smartphones do a doctor's job

Vitor Pamplona isn’t a doctor. He’s not even an optician. He can’t write you a prescription for glasses, or sell you a pair. Still, he’s pretty sure he’s going to disrupt the $75 billion global eye-care market.

At EyeNetra, the startup he cofounded, goofy curiosities like plastic eyeballs line the shelves, and a 3-D printing machine whirs in the background. It’s printing out prototypes of a device that will attach to your smartphone and, in a minute or two, tell you what kind of eyeglasses you need.

A material that could make solar power "dirt cheap"

A new type of solar cell, made from a material that is dramatically cheaper to obtain and use than silicon, could generate as much power as today’s commodity solar cells.

Although the potential of the material is just starting to be understood, it has caught the attention of the world’s leading solar researchers, and several companies are already working to commercialize it.

How the bacteria in your gut may be shaping your waistline

A calorie is a calorie. Eat too many and spend too few, and you will become obese and sickly. This is the conventional wisdom. But increasingly, it looks too simplistic. All calories do not seem to be created equal, and the way the body processes the same calories may vary dramatically from one person to the next.

This is the intriguing suggestion from the latest research into metabolic syndrome, the nasty clique that includes high blood pressure, high blood sugar, unbalanced cholesterol and, of course, obesity. This uniquely modern scourge has swept across America, where obesity rates are notoriously high. But it is also doing damage from Mexico to South Africa and India, raising levels of disease and pushing up health costs.

Scientists reveal how organic mercury can interfere with vision

More than one billion people worldwide rely on fish as an important source of animal protein, states the United Nations Food and Agriculture Organization. And while fish provide slightly over 7% of animal protein in North America, in Asia they represent about 23% of consumption.

Humans consume low levels of methylmercury by eating fish and seafood. Methylmercury compounds specifically target the central nervous system, and among the many effects of their exposure are visual disturbances, which were previously thought to be solely due to methylmercury-induced damage to the brain visual cortex. However, after combining powerful synchrotron X-rays and methylmercury-poisoned zebrafish larvae, scientists have found that methylmercury may also directly affect vision by accumulating in the retinal photoreceptors, i.e. the cells that respond to light in our eyes.

Valley Fever, the archaeologist’s scourge

This past June a federal judge ordered the relocation of thousands of prisoners from two prisons in the San Joaquin Valley in California to protect imprisoned men against a small fungus, Coccidioides immitis, that could infiltrate the gated and locked Pleasant Valley and Avenal state prisons and continue to cause isolated cases of a debilitating illness, valley fever.

The fungus, commonly referred to as cocci, has an ancient relationship with the desert soil of the western United States, as much a part of the ecology and flora of the San Joaquin Valley and the “lower Sonoran life zone” as the equally hardy saguaro, creosote and prickly pear cacti that dot its landscape. This is an old New World infection that has plagued various communities in the American southwest for centuries now, from pre-Columbian Indians to Army Air Corps servicemen during WWII to Californian prisoners.

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