As it is with so many innovations, the idea for contact lenses can be traced back to the great Leonardo da Vinci. He was, as usual, way ahead of his time: Although Leonardo conceived of contact lenses in the 1500s, they weren’t commercially developed for several hundred more years.
Leonardo’s idea certainly caught on: According to recent estimates, contact lenses are worn by 135 million people around the world—a figure that includes more than 35 million Americans.
Their primary use is, of course, to enhance vision, but they are worn for several other reasons. One is aesthetic. Although it seems to be “cooler” now than at any time in recent history to wear glasses—thank you Bono and Tina Fey—millions of people don’t want anything to do with them. Contact lenses also have other benefits—they don’t steam up, they aren’t affected by wet weather and they offer users a wider field of vision than glasses.
For years, researchers have been eyeing other uses for contact lenses, with one of the most promising being drug delivery. Eye drops are the most frequently used mechanism for delivering drugs to the eye, but they are inherently inefficient: either our tears wash away most of the medicine before it can be absorbed or it ends up in a tissue. In addition, some eye-drop regimens are very challenging, requiring administration several times a day. It is very easy for patients, especially elderly ones, to simply forget to take their medicine.
So, researchers are looking into whether or not drugs designed to treat eye disease can be delivered via contact lenses instead of drops—a method that could be very efficient, and one that would free patients from have to remember to dose themselves.
Work to develop contact lenses that function as efficient drug-delivery vehicles is underway on several fronts. One promising effort was described in a recent article in Medill Reports, which is published by Northwestern University. The article profiles a Harvard Medical School team that since 2007 has been developing a contact lens to deliver antibiotics to the eye.
The Harvard team’s mission was “to design a lens that was comfortable, compatible with the body and deliver a constant amount of medicine.” The solution it came up with sounds pretty sophisticated: “a biodegradable dual-polymer delivery system within a lens built from pHEMA, the plastic material used in manufacturing today’s lenses.”
To test its invention, the team infused the lens with a common antibiotic and dropped it rather ominous-sounding solution “teeming with staph bacteria recovered from patients with cornea, eyelid and tear-duct infections.” The results were promising: “The contact successfully released its medicine at a constant rate, sometimes for as long as 100 days, and cleared the infection.”
The article goes on to discuss other potential uses for contact lenses that sound as though they sprang from the mind of an over-caffeinated science fiction writer, including serving as “bionic eyes” and monitoring blood pressure or insulin. Amazing ideas worthy of Leonardo da Vinci himself.
It’s an age-old question: Why did the chicken cross the road?
And here’s an answer you’ve never heard before: To see all that colorful stuff on the other side.
As the results of a recent study indicate, chickens do a better job of perceiving color than you and I, which researchers attribute to the way their retinas are organized and structured.
The study mapped five types of light receptors in the eyes of chickens. It determined that their light receptors are laid out in “interwoven mosaics” that maximize their ability to see many colors throughout the retina.
Dr. Joseph C. Corbo, of Washington University School of Medicine in St. Louis, Missouri, the study’s author, says, “The color receptor organization in the chicken retina greatly exceeds that seen in most other retinas and certainly that in most mammalian retinas.”
Why would chickens end up with better color vision than us? Somehow, it just doesn’t seem fair.
The answer likely can be found in the evolutionary history of poultry and other bird species; specifically, their dinosaur ancestry. Dr. Corbo speculates that birds developed acute color vision because they did not spend any part of their evolutionary history in the dark. Apparently, while dinosaurs were out cavorting during the day, most mammals became nocturnal (a logical way to avoid becoming a meal for T-Rex and his friends).
Because they do not have a lengthy nocturnal period in their history, birds developed more retinal cone cells (which function best in relatively bright light) than mammals. Cones are also the vision cells responsible for color perception, and different cones detect different wavelengths of light. You and I have three kinds of cones that allow us to see red, green and blue. But birds have an extra cone, which allows them to see violet and ultraviolet light.
This line of research is important because it may help pave the way for the use of stem cells and other new techniques to treat the nearly 200 genetic disorders that can cause various forms of blindness.
What may be surprising is the connection between Dr. Corbo’s research and Acucela. Because mammals spent much of evolutionary history as being nocturnal, we developed rod photoreceptors and ultra-sensitive retinas, compared to chickens’ cone-photoreceptors, which are more tolerant to light. It is our rod dominance that is believed to be the underlying cause age-related macular degeneration (AMD). With excessive daytime light exposure, the rods will be over stimulated and produce toxic byproducts, including A2E, which is implicated in AMD. Because rod photoreceptors are also known to be more susceptible to the prolonged light exposure, we want to specifically avoid the over stimulation of rod photoreceptors, to reduce the accumulation of toxic byproduct and subsequent cell death. This is the underlying scientific base for Acucela’s visual cycle modulation treatment paradigm for the treatment of dry AMD.
So let’s not be jealous of our feathered-friends’ outstanding color vision—our understanding of it may prove to be very helpful in treating human vision problems in the future.
Most likely, you can’t, and neither can I. If we hit a piano key or pluck a guitar string, only our sense of hearing is stimulated.
But can you imagine what it would be like if every time you heard a musical note you also saw a specific color? And when you heard a song or a symphony, all the colors merged together along with the sounds?
That’s what experiencing music is like for Laura Rosser, featured in this ABC News profile, and other people who live with synesthesia, also referred to as “cross-wired” senses.
Synesthesia is an involuntary joining of the “real information” of one sense with perception in another sense. The additional perception is regarded by the synesthete as real—something outside the body, rather than imagined.
There are several synesthesia variations, with different manifestations. For some synesthetes, numbers and letters are always associated with specific colors. For others, different numbers and letters have unique personality traits (the letter “T” might be “friendly,” the letter “W” not so much). In another form of the condition, words are associated with tastes. And for some people, tastes are associated with shapes (one food is “round,” another “triangular”).
The condition is still something of a mystery: According to the American Synesthesia Association, “although synesthesia has been known for the past 300 years, it is only in the last two decades or so that it has been seriously studied by scientists.”
The ASA attributes growing awareness of the condition to two technological advances: the development and use of functional MRI and the Internet. According to the association, “the use of functional MRI scans has launched numerous scientific studies worldwide, and the Internet has permitted synesthetes, for the first time in history, to learn more about their abilities and to be in touch with one another.”
Famous synesthetes include artist David Hockney, author Vladimir Nabokov, piano rocker Billy Joel and jazz great Duke Ellington, who told a biographer, “I hear a note by one of the fellows in the band and it’s one color. I hear the same note played by someone else and it’s a different color.”
Many synesthetes consider the condition to be a gift, rather than a disability.
“I see it as a spiritual, God thing that enables more intuition,” Laura Rosser told ABC News. “It really is an added dimension to what I do.”
Daniel lost his vision to cancer as infant, but as a child he learned to navigate his surroundings by teaching himself a technique he calls “flash sonar”—he clicks his tongue and listens to the echoes to create a mental map of what is around him. The technique, also called echolocation, is similar to the method bats and dolphins use to get around. Daniel compares it to shining a flashlight into the dark—the difference being that the “illumination” comes from sound instead of light.
Daniel is the co-founder and president of World Access for the Blind, which is working on “improving the quality of interaction between blind and sighted people by facilitating equal access to the world’s resources and opportunities.” The organization’s philosophy is perhaps best summed up by its “no limits perspective,” which states: “Our students are grounded in the knowledge that limits are to be self chosen, not imposed by others.”
Daniel was recently profiled by The Discovery Channel series “Is It Possible?” In the episode you can watch him ride a bike using the “flash sonar” technique and teach the method to a young student. Many more videos of Daniel and others using the technique are available here.
Daniel is truly a remarkable person, and it is wonderful that he is helping to spread awareness of such a useful mobility technique.
As someone who loves the United States, I am looking forward to the pageantry, parades and fireworks that accompany its annual anniversary celebration.
But as a father and an ophthalmologist, I am not looking forward to the inevitable and tragic news stories that are inevitable in the wake of the holiday; every year there are far too many accounts of people—primarily children—who sustain severe injuries from the pyrotechnics associated with the holiday.
If you are considering purchasing fireworks or firecrackers to celebrate the Fourth of July, I have two words for you: Please don’t.
According to Prevent Blindness America, a leading volunteer eye health and safety organization, fireworks were implicated in an estimated 9,800 injuries treated in U.S. hospital emergency rooms in 2007 (the latest year for which the organization had data). About two-thirds of those injuries were sustained in the one-month period surrounding the July 4th holiday, and some 1,500 of those injuries were to the eye.
Pyrotechnics don’t have to blow up to be dangerous. “Sparklers” seem fairly benign, at least in comparison to many other types or fireworks or firecrackers, but they burn at 1,800 degrees Fahrenheit and can cause severe burns. The absolute last thing you want to do is put these devices into the hands of children or let children near them; nevertheless, the Consumer Product Safety Administration reported that during a recent July 4th holiday period, sparklers accounted for one-third of the fireworks injuries to children less than five years of age.
So, to protect your eyes and the eyes of the people you love, I urge you follow this great advice from Prevent Blindness America:
Do not purchase, use or store fireworks or sparklers of any type
Protect yourself, your family and your friends by avoiding fireworks and sparklers
Attend only authorized public fireworks displays conducted by licensed operators, but be aware that even professional displays can be dangerous
I wish you and your family can a fun, memorable and very safe July 4th holiday!
Here are a few eye-health-related news items that caught my eye in recent weeks:
Photo by: jj99smith
Check-in, in the blink of an eye
Can you imagine checking into a hotel simply dialing into an automated line and then looking at your phone? That’s one potential outcome of the next-generation of iris-scanning technology, as described in a recent Forbes article. Amazing stuff.
Photo by: joshgard
Do migraine sufferers have more difficulty tuning out visual stimuli?
The first recourse for many people who suffer from migraine headaches is seek out solace in a dark, quiet room. New research indicates the way they process visual information may be what drives them there. In Investigative Ophthalmology & Visual Science, researchers from Scotland’s Glasgow Caledonian University had migraine sufferers identify a small area of light on a screen with and without accompanying visual “noise.” The results indicated that when the visual noise was not present, people prone to migraines could distinguish the area of light as well as the control group; however, when the noise was added, the migraine sufferers performed significantly worse. A researcher associated with the study said that people who suffer from migraines might benefit by avoiding “scenes overloaded with visual distracters, for example computer screens and learning tools which have a lot of visual information on them.”
Photo by: wnyc
Dr. Sacks Looks at Vision
This is a fascinating interview with Oliver Sacks, the neurologist and author, who has long been intrigued by vision. His forthcoming book, The Mind’s Eye, was sparked, in part, by his own battle with ocular melanoma, which cost him much of the vision in his right eye and led to him experiencing what he calls “fairly simple geometrical hallucinations.” I expect it will be a great read, especially for those of us who share Dr. Sacks’ interest in how we process visual information.
In an article this spring, the New York Times took a rather wary look at the burgeoning field of “vision therapy,” whose adherents, the paper reported, claim it can successfully treat a range of disorders in children including “reading problems, learning problems, spelling problems, attention problems, hyperactivity and coordination problems.”
Vision therapy is practiced by “behavioral optometrists,” who are termed in the article as “part of a growing subspecialty of optometry that takes the traditional practice beyond its usual focus on eye health and eyesight.”
The treatment regimen associated with vision therapy can seem unorthodox, to say the least. According to the Times reporter, a visitor to a vision therapy center “might see children standing in hula hoops, dodging balls suspended from strings, looking through prisms that give them double vision and then trying to fuse the image, playing Wii-like games for balance and ‘visual thinking’ or pointing to bright spots blinking on a light box for hand-eye coordination.”
A recent Google search on the term “vision therapy” yielded 235,000 hits leading to sites that promise “special programs for learning related visual problems,” to “boost reading comprehension scores” and to “help ADD.”
The treatment is naturally attractive to the parents of children having trouble in school, who frustrate easily, are poorly motivated or have other learning or behavioral issues. A diagnosis of a vision problem may be easier to accept than one of dyslexia or ADD—and also offer the promise of being easier to treat and manage. And, indeed, the Times article includes interviews with several parents who say they are extremely pleased with the results their children seem to have obtained from vision therapy.
But despite the anecdotal evidence supporting it, my colleagues in the American College of Ophthalmology do not consider vision therapy effective for treating learning disorders and other related problems. And they are supported in this view by the American Academy of Pediatrics, the American Association for Pediatric Ophthalmology and Strabismus and the American Association of Certified Orthoptists (AACO).
Last year those organizations put out a joint statement that said in no uncertain terms, “There is no valid evidence that children participating in vision therapy are more responsive to educational instruction than children who do not participate.”
The groups advise that “children with learning disabilities should receive individualized, evidence-based educational interventions combined with psychological and medical treatments as needed.”
By all means, have your child’s eyes examined and follow your eye physician’s advice regarding any necessary corrections and treatment. But please be very careful before you place your confidence in vision therapy to cure a learning disability or behavioral problem.
Chances are you’ve never heard of Charles Bonnet, or even of the eye condition that bears his name. But his story, and the nature of the condition was the first to diagnose, are both very interesting.
Bonnet was a Swiss philosopher and naturalist who lived from 1720-1793. In 1760, he noted that his 87-year-old grandfather, who suffered from near-total vision loss due to cataracts, was seeing things. Literally. His complex, vivid visual hallucinations included men, women, birds, buildings, tapestries and carriages. His grandfather was otherwise in good health, both mentally and physically.
The condition Bonnet first noted 250 years ago is now known as Charles Bonnet syndrome. One reason for a lack of general awareness about it may be due to the stigma associated with visual hallucinations: people who experience them may naturally fear they have a mental illness, and thus be reluctant to report them.
But, as is the case with Charles Bonnet syndrome, visual hallucinations are not necessarily symptomatic of mental illness, or of an underlying serious condition such as Parkinson’s disease and Alzheimer’s disease, with which they are sometimes associated.
According to Lighthouse International, roughly one third of people with low vision develop Charles Bonnet syndrome. That includes people with serious eye conditions including age-related macular degeneration, cataracts, diabetic retinopathy, and other eye disorders. The hallucinations are more likely to occur while awake, alone, and in dim light, or during periods of physical inactivity.
The visual hallucinations associated with Charles Bonnet syndrome usually dissipate within a year or 18 months, apparently because of adjustments the brain makes to accommodate vision loss. Although treatment is available, once patients are reassured that their visual hallucinations are not symptomatic of mental illness or serious disease, many learn to live with them.
It goes without saying that you should report any changes to your vision—which certainly includes seeing things that you know aren’t there—to a physician, but I will say it anyway. It may be a difficult call to make, but it will be an important one.
Probably no company is better at inspiring excitement and devotion than Apple Computer. Although never the PC market-share leader, it has certainly managed to corner the market on devotion with innovative, well-designed products like the Macintosh, the iPod and the iPhone.
And, of course, it was hard to miss the April debut of the iPad, which got a build-up worthy of a Hollywood summer blockbuster.
Although Apple says initial demand for the iPad exceeded its expectations, only time will tell if the company has succeeded in redefining personal computing with its new tablet. In the meantime, we’ve been wondering if the iPad is, as some claim, going find a niche with people with visual impairments.
Even before the introduction of the iPad, Apple had earned a lot of goodwill among accessibility advocates for the features it builds into its computers, iPods and the iPhone that make them more usable for people with impaired vision and other disabilities.
And right out of the gate, Apple made it clear that they had not overlooked people with disabilities when it designed the iPad, boasting on a page devoted to iPad accessibility that the device “comes standard with accessibility features that help people with disabilities experience all that it has to offer.”
One of those features is “VoiceOver,” a technology that enables audible control of every menu the user encounters, even those included in third-party applications. In addition, the iPad’s zoom feature allows users to magnify the entire screen of any application up to five times normal size. There are other built-in visual aids and also features that make using the iPad easier for the deaf and hard of hearing.
The inclusion of VoiceOver with the iPad was commended by the National Federation of the Blind, which said in a statement that, “By integrating accessibility into its products, Apple is setting an example that we believe the rest of the electronics industry should follow.”
Some reviewers have termed the iPad as essentially a larger version of the iPod Touch, but according to The Wireless Review, a website that assesses technology with the disabled community in mind, that’s a good thing for people with visual impairments. “The Touch’s touchscreen and overall user interface design are intuitive and visually accessible. The much larger screen on the iPad…should improve accessibility for people with low vision and other partial vision impairment.”
But the same review also decries the lack of a camera with the iPad, noting “cameras are increasingly used in conjunction with GPS functionality by software applications for augmented reality, mixed reality and location-based services.”
Whether or not the iPad proves to have staying power, either with electronics consumers in general or members of the disabled community, I think it’s great to see Apple making what looks like a genuine attempt to make their products as accessible as possible. That’s good business—and good for their business.
I recently came across a real-life story that sounds as though it sprang from the imagination of a Hollywood screenwriter.
It’s the saga of Mike May, who was blinded at the age of three years old in a freak accident. Despite his disability, he lived a life of incredible accomplishment. He worked for the CIA, excelled in business and in sports (including becoming a champion skier and setting a world-record speed record for a blind skier—65 mph!), traveled the world and raised a family.
In 1999, at the age of 46, long after he had given up on the idea of ever seeing again, a chance encounter with a very supportive ophthalmologist presented him with the opportunity to undergo an extremely risky stem-cell treatment that held the promise of partially restoring his vision
In addition to the risks associated with the treatment, history was against Mike. At the time of his surgery there had been fewer than 100 reports of people gaining vision after a lifetime of blindness. And those accounts were not all positive—adjusting to having vision after a lifetime without it can be enormously challenging.
But Mike risked the surgery, and it worked. He was able to see his wife and children for the first time as soon as his bandages came off, and play catch with his kids just a short time later.
But although he was profoundly grateful to save his sight back, Mike faced new challenges after it was restored. For instance, he was an expert blind skier—but he was back to being something of a novice once he had to process all of the visual information coming his way. In a CBS News interview several years after his operation, Mike discussed some of the issues he faced after the operation, which also included an inability to recognize faces, something doctors attributed to the withering of the visual pathways to the brain during four decades of blindness.
Mike is now the president of The Sendero Group, a company that develops technology to enhance the mobility of the visually impaired. On the Sendero Group website, a page is devoted to photographs of Mike—including shots of his bandages being removed after surgery and his first glimpses of his family.
Focus on Your Vision follows Dr. Ryo Kubota’s quest to unlock the science behind new ways to treat dry AMD, dry eye and other eye diseases and restore and protect the vision of countless patients suffering from these conditions. Join the conversation as he shares his story, his vision and his knowledge of eye diseases and along the way highlights the promising treatments of tomorrow. Please send your questions or feedback to Dr. Ryo on the Contact page.
About AMD
One of Dr. Ryo Kubota’s primary focus areas of research at Acucela is dry age-related macular degeneration, or “dry AMD.” This eye disease affects more than 26 million people worldwide and is the leading cause of blindness in people over age 50. Still, there is no cure or currently approved treatment for dry AMD. Acucela is also working on a treatment for dry eye, which has more than 10 million sufferers in the U.S. alone. Learn more about Acucela’s approach to combating AMD.
