New Eye Drops Improve Aging Vision Without Glasses. Here’s How They Work


When people get into their 40s beyond, their close-up vision starts to worsen. For many people, cranking up the font size on a phone or maxing out the brightness on a computer is the only way to be able to read some text.

 

This condition is known as presbyopia, it affects around 128 million people in the US more than a billion people worldwide.

In late 2021, the US Food Drug Administration approved a new eye drop medication to treat presbyopia. As an optometrist, I was initially skeptical.

Prior to the release of these eye drops – called Vuity – people would either need glasses, contacts or eye surgery to alleviate presbyopia. But after learning how these eye drops work, I recognized that for many people, they could offer an easier safer way to see clearly again.

Pupil lens are important parts of the eye involved in focusing on objects. (ttsz/iStock/Getty Images)

How eyes focus

Many parts of the human eye interact with incoming light to produce a clear image.

The first thing light hits is the cornea, the clear outer layer that initially bends the light. Then light passes through the iris pupil, which can shrink or grow to let more or less light into the inside of the eye. It then travels through the lens, which further bends the light precisely focuses it onto the center of the retina. Finally, the light signal is transferred to the optic nerve at the back of the eye, for the brain to interpret as an image.

 

To produce a clear image, your eyes need to adjust to how far away an object is. Your eyes take three major steps to focus on objects close to your face: your eyes point toward the object you want to look at, your lenses change shape your pupils constrict.

Once you point your gaze at what you’re interested in, a small muscle in the eye contracts, which changes the shape of the lens to make it thicker. The thicker the lens is, the more the light bends as it passes through. At the same time, your pupils constrict to block some of the incoming light from other objects in the distance.

When light bounces off an object enters your eye, the rays of light at the center are what provide a clear image. Blocking the scattering light by constricting the pupil helps to sharpen the image of close objects.

You can simulate this process using a camera on your cellphone. First, point the camera at something in the distance. Then, move your thumb into the image, holding it about 6 inches away. Your thumb will start off blurry, but as the camera’s lens changes shape, your thumb will come into focus.

(BruceBlaus/WikimediaCommons/CC BY-SA)

IMAGE: Presbyopia stiffens the lens in the eye, when a person can’t bend their lens as easily, they are unable to focus incoming light on the correct part of the retina images appear blurry.

What is presbyopia?

Presbyopia is the inability of the eyes to focus on close objects, which results in blurry images. It begins when people are in their 40s progresses until it plateaus around the age of 60.

Researchers know that age is the main driver of presbyopia, but there is an ongoing debate over the mechanical causes at its root.

 

One theory suggests that as lenses age, they get heavier can’t change shape as easily. Another theory suggests that the muscle that pull on the lens become weaker with age. I suspect presbyopia likely occurs due to a combination of both.

Regardless of the cause, the result is that when looking at close objects, people’s eyes are no longer able to bend incoming light enough to direct it at the center of the retina. Instead, the light is focused at a place behind the retina, resulting in blurry vision.

How the eye drops work

Remember, there are two major things an eye does to focus on close objects: the lens changes shape the pupil gets smaller. Since presbyopia limits the ability of the lens to change shape, these eye drops compensate by causing the pupil to get smaller.

Constricting the pupil reduces the amount of light scatter. This makes it so that the light entering the eye is better concentrated onto the retina, thus creating a wider range of distances where objects are in focus allowing people to see both close far objects clearly.

 

Once you put the drops in your eyes, it takes about 15 minutes for the active ingredient, pilocarpine, to begin working. Pilocarpine is a medication that was first discovered in the late 1800s, can treat conditions such as glaucoma ocular hypertension. The effect on pupils lasts for about six hours.

Smaller pupils mean that less light gets into the eye. While this isn’t a problem during the day when there is a lot of sun, it can cause difficulty seeing in low-lighting conditions. Aside from these downsides, the most common side effects of the drops are headache red eyes.

(MikeRun/WikimediaCommons/CC BY-SA)

IMAGE: Making the pupil smaller allowing less light into the eye increases depth of field, making closer objects appear in focus – as seen in diagram a above – compared to a larger pupil narrower depth of field as seen in diagram b.

Presbyopia in the future

Vuity is currently approved for once-daily use in each eye. A bottle will cost around US$80, requires a prescription will last for nearly a month if used daily. For some people, it could be a great alternative or adjunct to glasses or surgery.

While Vuity may be the first FDA-approved eye drops to treat presbyopia, researchers are studying a number of other approaches. Some are developing eye drops that include non-steroidal anti-inflammatory drugs to help constrict the pupil – similarly to Vuity.

Other teams are studying drops that soften reduce the weight of the lens to promote easier focusing. Finally, some early research has shown that pulsed electrostimulation of eye muscles can help strengthen them improve people’s ability to bend their lenses. The Conversation

The future of presbyopia treatment is exciting as researchers work on many potential ways to overcome this universal condition of old age. For now, Vuity – while not a magic cure for everyone with presbyopia – is an innovative option may be worth asking your eye doctor about.

Robert Bittner, Assistant Professor of Ophthalmology, University of Pittsburgh Health Sciences

This article is republished from The Conversation under a Creative Commons license. Read the original article.

 



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Scientists Just Found a Vast Aquifer of Ancient Seawater Below Antarctica


Beneath a fast-flowing ice stream in West Antarctica, scientists have discovered a vast aquifer brimming with seawater that’s likely been locked down there for thousands of years. 

 

This is the first time scientists have detected groundwater beneath an ice stream in Antarctica, the discovery could reshape our understanding of how the frigid continent reacts to climate change what kinds of mysterious organisms lurk beneath its many ice shelves.   

The newfound groundwater system can be thought of as a giant sponge, made up of porous sediment saturated with water, said Chloe D. Gustafson, lead author of a new study on the buried aquifer, formerly a geophysicist at Columbia University’s Lamont-Doherty Earth Observatory now based at UC San Diego’s Scripps Institution of Oceanography.

“The ‘sponge’ that we observe is anywhere from half a kilometer to about two kilometers thick [0.3 to 1.2 miles], so it’s pretty deep,” she told Live Science.

Gustafson her colleagues described the sizable aquifer in a report published Thursday (May 5) in the journal Science. The aquifer lies beneath the same ice stream as a subglacial lake called Lake Whillans, which sits at a shallower depth, about 2,625 feet (800 meters) under the ice.

“For me, the most surprising result is the sheer volume of water held inside the aquifer,” said Winnie Chu, a glacier geophysicist at the Georgia Institute of Technology’s School of Earth Atmospheric Sciences, who was not involved in the study.

The authors estimated that the enormous aquifer holds more than 10 times the volume of water contained in the shallower system of lakes rivers found at the base of the ice shelf. This shallow system includes Lake Whillans, which measures 20 square miles (60 square kilometers) in area is about 7 feet (2.1 m) deep.

 

Related: Unimaginable diversity of life discovered beneath Antarctic ice shelf

‘An MRI of the Earth’ 

Scientists have long speculated that huge aquifers might lie hidden beneath Antarctic ice, in part because the continent’s ice streams glaciers glide over a bed of permeable sediment that water should be able to penetrate, Chu said.

However, until now, technological limitations prevented researchers from gathering direct evidence of such deep hydrological systems, meaning systems made up of water, she explained. Instead, research focused on relatively shallow lakes rivers found at or near the base of glaciers ice shelves.

To peer beyond these shallow systems into the hidden depths below, Gustafson her colleagues used a technique called “magnetotelluric imaging”. They took measurements from the Whillans ice stream in West Antarctica, a moving belt of ice that measures about 0.5 miles (0.8 km) thick moves about 6 feet (1.8 meters) per day in its flows towards the nearby Ross Ice Shelf.

Magnetotelluric imaging relies on electromagnetic fields generated by solar winds interacting with Earth’s ionosphere – a dense layer of molecules electrically charged particles in the upper atmosphere.

 

When solar winds strike the ionosphere, they excite the particles within generate moving electromagnetic fields that penetrate Earth’s surface. These moving fields then induce secondary fields in the ice, snow sediments, it’s these secondary fields that the magnetotelluric instruments measure. The team buried these instruments in shallow pits in the snow gathered data from roughly four dozen different locations on the ice stream.

“These secondary fields are really tightly coupled to geology hydrology, specifically,” which means that ice looks very different from sediments, salt water looks different from freshwater, so on, Gustafson said.

“This is like taking an MRI of the Earth, our signal just comes from the sun interacting with Earth’s magnetic field,” she said. 

Related: Massive iceberg narrowly avoided collision with Antarctic ice shelf 

Other teams of scientists had used this mega-MRI in Antarctica before, to examine Earth’s crust upper mantle; these studies started as early as the 1990s, according to a 2019 review in the journal Surveys in Geophysics.

Gustafson’s team, instead, took measurements from a shallower depth, extending from the base of  the stream to about 3 miles (5 km) down. There, they discovered a thick, sediment sponge with incredibly salty seawater at its deepest depths freshwater near its shallowest part, where the sponge approached the ice stream. 

 

This gradient suggests that the shallow, subglacial systems link up to the deep-seated aquifer, that both likely influence the flow of ice above, Gustafson said.

“Right now, it isn’t clear if the aquifer can exchange water from time to time with the subglacial hydrology or is it a one-way transfer,” where water from the ice stream trickles down then remains stored in the aquifer for some time, Chu said. 

Depending on the scenario, the aquifer may be lubricating the ice stream by periodically injecting water into the subglacial system or it may be removing water from the system; both of these dynamics would affect the flow of the ice stream above, Chu added.

The exchange of water between the deep system shallow system could also affect what types of microbial life grow beneath the ice stream how those microorganisms survive, Gustafson said. That’s because the flow of liquid water through the aquifer interconnected lakes rivers above drives the flow of nutrients through the ecosystem. Plus, the gradient of saltwater to freshwater shapes what kinds of microbes can survive in each environment.

Related: Microbes that feast on crushed rocks thrive in Antarctica’s ice-covered lakes

Regarding the saltiest water in the depths of the aquifer, the authors hypothesized that the water likely flowed from the ocean into the groundwater system some 5,000 to 7,000 years ago, during a warm period in the mid-Holocene epoch when the West Antarctic ice sheet was in retreat.

Then, “as the ice sheet readvanced, the presence of thick ice cut off ocean access to the bed, the remnant seawater was sealed as groundwater beneath the Whillans ice stream,” Chu wrote in a commentary of the study, also published May 5 in Science.

The aquifer beneath the Whillans ice stream is the first to be detected, but the research team suspects that such hydrological systems lie beneath all the ice streams in Antarctica, are just waiting to be discovered. These groundwater systems likely “extend hundreds of kilometers back into the ice sheet interior,” Gustafson said. The next step will be to gather evidence of such systems elsewhere on the continent compare what they found at Whillans to other regions. 

In particular, how might the aquifer beneath the rapidly-thinning Thwaites glacier – otherwise known as the “Doomsday Glacier” – differ from the one under Whillans, how do these deep systems affect the flow melt of the ice above? Current models of ice flow don’t factor in such aquifers, so that will be an interesting area of research going forward, Gustafson said. 

“There is still so much we need to learn about the interconnection between groundwater hydrology the rest of the ice sheet hydrology before we can say anything concrete about how groundwater hydrology may alter the effects of climate change on Antarctica,” Chu said.

Related content:

Half of Antarctic ice shelves could collapse in a flash, thanks to warming

Sudden collapse of Antarctic ice shelf could be sign of things to come

Giant crack frees a massive iceberg in Antarctica 

This article was originally published by Live Science. Read the original article here.

 



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Stanford to Launch New Climate Change School This Fall


The venture capitalist John Doerr his wife Ann have donated more than a billion dollars to fund a new school at Stanford University, the university announced yesterday (May 4). The Stanford Doerr School of Sustainability will launch in September of this year focus on addressing interdisciplinary solutions to climate change. Several other donors contributed a combined $590 million, giving the school a starting endowment of $1.69 billion.

John Ann Doerr

Edward Caldwell/Stanford University

The $1.1 billion gift is the largest amount ever given to found a single school, the second largest gift ever awarded to an academic institution, according to the Chronicle of Higher Education, which tracks philanthropic donations in academia. Only former New York mayor Mike Bloomberg’s 2018 endowment of $1.8 billion for student financial aid to Johns Hopkins University exceeds it.

“Climate sustainability is going to be the new computer science,” John Doerr tells The New York Times. “This is what the young people want to work on with their lives, for all the right reasons.”

Doerr’s wealth is estimated at roughly $11 billion, stemming from his investments in companies such as Amazon, Google, Slack. The Times reports that Doerr was first spurred to support climate change initiatives after watching Al Gore’s film An Inconvenient Truth in 2006. A year later, Gore joined Doerr’s venture capital firm, Kleiner Perkins. Doerr has invested in several clean energy technologies—several of which failed in the 2008 financial crisis—last year published a book about climate change. “We’ve got to be clear about the problem,” he tells the Times. “I believe this is a problem of scale that needs far greater ambition, urgency excellence deployed against it.”

To begin, roughly 90 Stanford faculty—including all of those currently in the Stanford School of Earth, Energy, Environmental Sciences—will move from existing departments to the new school, according to the press release, with a goal of hiring an additional 60 faculty over the next decade. The school’s focus will center around eight fields, The Washington Post reports, including climate change, sustainable cities, energy technology, human society behavior. A “sustainability accelerator” within the school will promote solutions by identifying supporting the development of high-potential technologies policies. 

“These gifts will help Stanford bring its full effort to bear on solving the most complex problems in climate sustainability, on training the next generation of students who are eager driven to address these challenges,” Stanford President Marc Tessier-Lavigne says in the press release.

Stanford University mechanical engineer Arun Majumdar has been named as the inaugural dean of the school. Majumdar has advised the Obama Biden administration on energy issues. The school will be headquartered in what university officials call the Sustainability Commons, which will include two new flagship buildings, the existing Green Earth Sciences Research Building, the Jerry Yang Akiko Yamazaki Environment Energy Building. 

Not everyone has responded positively to the news. Speaking to the Times, David Callahan, author of The Givers: Wealth, Power, Philanthropy in a New Gilded Age, expressed disbelief that gifting money to an already “rich university” would do much to change things in the short term. “It’s nice that he’s parting with his money, but that billion dollars could be better spent trying to move this up on the scale of public opinion. Until the public sees this as a top tier issue, politicians are not going to act.”

David Ho, a climate scientist at the University of Hawaii at Manoa, shared on Twitter that he also thought the money could have been better invested, saying “I’d like to see someone give $1.1 billion to state universities [historically Black colleges universities] to study climate change.” 

In addition, there has been some blowback about the school’s decision to partner with fossil fuel companies looking to invest in clean energy. Stanford has so far resisted calls by students to divest its endowments from such companies—a process that other universities, including Harvard University Dartmouth College, have undertaken in recent years, according to Inside Higher Ed. Majumdar tells the Times that he is open to collaborating with companies “that want to diversify be part of the solutions.” (Majumdar is the Jay Precourt professor at Stanford University, an endowed chair named after a businessman who made his fortune in the oil industry.)

Jason Bordoff, a cofounding dean of the Columbia Climate School, tells the Post that when his school was created in 2020, “the vision for success was that years from now there would be numerous schools focused on climate change, we’d look back wonder how we ever thought we could tackle a problem of this complexity without universities making the strongest commitment they can to climate action through entire schools focused on the problem. . . . We need all hands on deck right now in climate philanthropy climate scholarship, John Doerr’s historic gift is an extraordinary commitment to that work.”





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Can Covid Lead to Impotence?


For a respiratory disease, Covid-19 causes some peculiar symptoms. It can diminish the senses of smell taste, leave patients with discolored “Covid toes,” or even cause a swollen, bumpy “Covid tongue.”

Now scientists are examining a possible link to an altogether unexpected consequence of Covid: erectile dysfunction. A connection has been reported in hundreds of papers by scientists in Europe North America, as well as in Egypt, Turkey, Iran Thailand.

Estimates of the magnitude of the problem vary wildly. A paper by Dr. Ranjith Ramasamy, director of reproductive urology at the University of Miami’s Desai Sethi Urology Institute, his colleagues found that the risk of erectile dysfunction increased by 20 percent after a bout with Covid. Other investigators have reported substantially higher increases in that risk.

When patients first started coming to Dr. Ramasamy’s clinic complaining of erection problems, “We dismissed it, thinking it was all psychological or stress induced,” he said.

But over time, he other physicians began to see a pattern, he said. “Six months after the initial infection, patients had gotten better overall, but they continued to complain of these problems,’’ including both erectile dysfunction low sperm counts, Dr. Ramasamy, who has written several papers on the topic, said.

At the outset of the pandemic, Dr. Emmanuele Jannini, a professor of endocrinology medical sexology at the University of Rome Tor Vergata, reported a strong link between erectile dysfunction Covid. When he compared men who had been ill with Covid with those who had not, he found that those who had been infected were nearly six times as likely to report impotence as those who had avoided the coronavirus.

“Communicating that the disease can affect your sexual life is a tremendously powerful message,” especially for men who still resist vaccination, Dr. Jannini said in an interview. “The evidence is very strong.”

Research from imaging scans biopsies indicates that the coronavirus can infect tissue within the male genital tract, where it may linger long after the initial infection. Scientists say it is too early to be certain that the link to erectile dysfunction is causal, since so many factors — psychological as well as physiological — play a role in producing maintaining an erection. The pandemic has led to social isolation a surge in anxiety depression, all of which may play a role.

“Men’s erections are more complicated than people think,” Dr. Justin Dubin, who co-wrote a paper about the adverse impact of Covid on men’s health, said.

“You need good blood flow, you need the nerves to be firing, you need good hormone levels, specifically testosterone,” he said. “But you also need to be in a good state of mind, you also need to be aroused. If any of these things go wrong, you may have an issue getting an erection.”

In that sense, the pandemic is the perfect confluence of converging factors for causing erectile dysfunction, Dr. Joseph Katz, a professor at Florida College of Dentistry, said. Dr. Katz stumbled on the issue of erectile dysfunction while investigating Covid’s effects on oral health.

Some researchers speculate that erectile dysfunction may be linked to the well-documented loss of the ability to taste smell experienced by Covid patients, because these senses play an important role in sexual arousal. “It is through smells that the arousal mechanism in the brain is ignited,” three Italian urologists wrote last year in a letter responding to Dr. Jannini’s paper.

At the very least, men need healthy blood vessels good blood flow in order to develop sustain erections. The coronavirus may damage blood vessels the lining of the vessels, called the endothelium, as it binds to the molecular receptors that are plentiful on endothelial cells.

The vessels may not constrict stretch as needed to allow for blood flow to the penis. Injury to the blood vessels may also contribute to more serious complications of Covid, like heart attacks, strokes abnormal clotting.

“Our entire vascular system is connected — it’s not an isolated penis problem,” Dr. T. Mike Hsieh, director of the men’s health center at University of California, San Diego, said.

But vascular problems can manifest in the sexual organs first, because the vessels there are so small. (Dr. Jannini calls erectile dysfunction “the canary in the coal mine” for cardiovascular disease.) Erectile dysfunction cardiovascular disease share risk factors — such as being severely overweight, having metabolic diseases like diabetes, smoking older age — which also increase the odds of having severe Covid.

“The artery for the penis is one-tenth the size of a coronary artery, when you have a narrower vessel, whether it’s a plumbing problem or a vascular problem, it will show up there first, even before you see it in a larger artery,” Dr. Hsieh said.

Erectile dysfunction can precede a heart attack by about five years, he said, can be an early signal that there are other underlying risk factors.

“When I see a guy for erectile dysfunction, they don’t just get a Viagra or Cialis prescription,” Dr. Hsieh said. “They get a referral to a primary care colleague or a cardiologist to make sure their cholesterol is in check, their diabetes is under control, to discuss weight management, lifestyle or dietary changes.”

Erectile dysfunction may point the way to better diagnosis of long Covid, Dr. Jannini said, or even deteriorating mental health.

“If you have a patient who survived Covid, you want to know if he has long Covid or not, just ask him how it’s going in bed,” Dr. Jannini said. “If he’s having a normal sex life, the possibility of him having serious long Covid is very, very low.”

Left untreated, erectile dysfunction can lead to further complications. Cases of Peyronie’s disease, a condition that causes curved, painful erections as a result of fibrous scar tissue built up in the penis, orchitis, the inflammation of one or both of the testicles, have developed in men who have had Covid, according to published research.

Men who don’t have normal erections for several months at a time may develop scar tissue fibrosis, which makes erectile dysfunction harder to treat may even lead to shortening of the penis.

Erectile dysfunction can resolve on its own, but Dr. Hsieh encouraged men with symptoms to see their physicians, sooner rather than later.

“If you’re having these problems, do not wait,” he said. “For the most part, we can get the guys’ sex lives back.”



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For a Shy Porpoise, Rare Good News


For a Shy Porpoise, Rare Good News

Catrin EinhornReporting on the animals who share the 🌎

To predict extinction, researchers used computer models that combined the genetic findings with other factors, such as birth rates. The results were clear: Vaquitas are very likely to survive if fishing deaths are stopped — but only if stopped entirely.

Even reducing the fishing deaths by as much as 80 percent would still lead to a 62 percent chance of extinction.

There’s basically no time left,” said Jacqueline Robinson, one of the study’s authors a postdoctoral genetic researcher. “Gill net fishing has to be halted immediately.”



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