If you’ve ever experienced motion sickness you know that it can cause nausea, sweating and headaches. But did you know what exactly causes it? WebMD tells us “You get motion sickness when one part of your balance-sensing system (your inner ear camera.gif, eyes, and sensory nerves) senses that your body is moving, but the other parts don’t.” There are several ways to deal with it including OTC medicines (such as Dramamine) and patches that go behind the ear. Now there is a new option for travelers…Anti Motion Sickness Glasses. “XPAND is a global immersive digital imaging technologies company that has been consistently delivering tour-de-force disruptive innovations through visionary technology development.” (http://www.xpand.me/company). XPAND recently developed these glasses to help minimize motion sickness. To find out more, visit the article featured in Vision Monday.
Originally posted on The VisionHelp Blog:
By now many of you have seen the adorable video about a young child who looks forward to seeing her eye doctor.
Well yesterday I had a first-in-my-career experience, a positive sign-of-the-times in many ways. A 10 year-old girl who received her first prescription for high bilateral hyperopia and astigmatism at around 14 months of age, and underwent patching as the sole treatment for amblyopia, decided to do her science fair project on the subject. After all, it was personal – and she delved into it in detail. In the course of discovering information online, she learned much more about amblyopia and its treatment possibilities than what her parents had been presented with by her pediatric ophthalmologist. She understood that while her doctor had done a great job at the level at which he treated her, there was apparently much more to amblyopia than how well she could read…
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Originally posted on Amcon GAZEtte:
Last weekend an impromptu overnight visit to my parent’s house resulted in me wearing my contact lenses all night. Normally i am vigilant about removing my contacts for overnight disinfection and storage. Surprisingly, though, when I work up, my eyes didn’t feel that bad, and I actually didn’t bother to take them out for the rest of the day.
Wearing my contacts all night is something I could have never done a few generations of contacts ago, which makes me think that contacts must have improved significantly since I started wearing them in the late 1980s.
If we look a bit farther back, we can really see an evolution of the contact lens. While the concept for the contact lens was first conceived in 1508 by Leonardo di Vinci, (yes, the artist), it wasn’t until 379 years later that one was actually made and tested. The first…
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St. Louis is fortunate to have a wonderful zoo with free admission. I love their slogan “Who’s watching who at the St. Louis Zoo?” Did you ever wonder which animals have the best vision? Scientists estimate that there are as many as 10 million species of animals on Earth. These are some of my favorites that have exceptional vision.
Dragonflies can see many more colors and details than humans due to their increased number of light sensitive proteins called opsins.They can also see UV light and have polarized vision.
Most insects have multifaceted eyes and dragonflies have the most at an estimated 30,000. Each one of these creates its own image. They have an almost spherical view.
Humans have 3 color receptive cones. The mantis shrimp has 16.
“Each eye possesses trinocular vision and depth perception” Wikipedia
Like dragonflies, they can see UV wavelengths and have polarized vision.
Birds of Prey
Birds of Prey, such as eagles, hawks and falcons, have especially large eyes which let in a lot of light and give a large view. Birds of prey also have a lot of receptors which maximize visual acuity. They have both a central and lateral fovea (most other animals have only one).
Birds focus on their target by changing the curvature of their eyes. They have great binocular vision because of the placement of their eyes.
Predatory birds such as eagles and hawks have the largest and most elaborate pecten of all the birds. The pecten supplies nutrients and oxygen throughout the vitreous humour of the eye, thereby reducing the number of blood vessels in the retina. With fewer blood vessels to scatter light coming into the eye, raptor vision has evolved to be the sharpest vision known among all organisms. (www.ebiomedia.com)
“The chameleon’s specialized vision and a specialized tongue-projection system permit the capture of insects and even birds from a distance. The chameleon’s eyes are very good at detecting and regulating light. The lens of a chameleon’s eye is capable of focusing extremely rapidly, and it can enlarge visual images much like a telephoto lens.” (www.britannica.com/animal/chameleon-reptile)
Four Eyed Fish
“Despite their name, four eyed fish have only two eyes. However, these eyes are divided by a band of tissue and each half of the eye has a pupil of its own. This bizarre adaptation allows the four eyed fish to see perfectly (and at the same time) both above and below the waterline, scanning for both prey and predators.
The upper half of the eyeball is adapted to vision in air, while the lower half is adapted to underwater vision. Although both halves of the eye use the same lens, the thickness and curve of the lens is different in the upper and lower eye halves, thus correcting for the different behavior of light in air and water. This means that when the four eyed fish is completely submerged, the upper halves of the eyes are out of focus. Fortunately, the fish spends almost its entire life in the surface, and it only has to dive completely once in a while to prevent the upper halves of the eyes from dehydrating.” (listverse.com)
Recently here in St. Louis we have been getting a lot of rain and hot temperatures. My glasses seem like they are constantly foggy or wet and I have to clean them several times a day. I tried wearing contact lenses before but I didn’t really like them. Many people around the world struggle with the same problems I do and about “40% of Americans who wear glasses” have considered LASIK (lasik.com).
So, how did LASIK come to be, what is it, and is it a good idea?
History (courtesy of Wikipedia)
In 1980, Rangaswamy Srinivasan, at the IBM Research laboratory, discovered that an ultraviolet excimer laser could etch living tissue, with precision and with no thermal damage to the surrounding area. Marguerite B. MacDonald MD performed the first human VISX refractive laser eye surgery in 1989.
The Food and Drug Administration (FDA) commenced a trial of the excimer laser in 1989. In 1992, under the direction of the FDA, Greek ophthalmologist Ioannis Pallikaris introduced LASIK to ten VISX centres. In 1998, the “Kremer Excimer Laser”, serial number KEA 940202, received FDA approval for its singular use for performing LASIK. Subsequently, Summit Technology was the first company to receive FDA approval to mass manufacture and distribute excimer lasers. VISX and other companies followed.
Since 1991, there have been further developments such as faster lasers; larger spot areas; bladeless flap incisions; intraoperative corneal pachymetry; and “wavefront-optimized” and “wavefront-guided” techniques. However, use of the excimer laser risks damage to the retina and optic nerve. The goal of refractive surgery is to avoid permanently weakening the cornea with incisions and to deliver less energy to the surrounding tissues.
LASIK stands for “Laser-Assisted-In-Situ Keratomileusis”. There are 2 parts to LASIK surgery: flap creation and corneal reshaping. The surgeon creates a flap using a laser or blade. This flap is lifted and then the surgeon uses and excimer laser to reshape your cornea (specifically the stroma layer). After the surgery is complete the flap will be replaced.
LASIK recovery time is low and most patients return to normal activities the day after surgery. Most of a patient’s normal vision is returned within several hours, but it can take several months to reach 100%. As with any medical procedure, there are some potential risks including infection, dry eyes, and halos.
About 80% of the adult population is a candidate for LASIK eye surgery. Many of them share key traits
* Age 18 and older
* Have a common vision problem (e.g. astigmatism, farsightedness, nearsightedness)
* Lead active lifestyles
* Cannot or prefer not to wear glasses and/or contact lenses
* Are in general good health
LASIK eye surgery ranges in cost depending on your location, provider, and insurance discounts. To determine if you are a candidate for LASIK, you can schedule a consultation with a provider of your choice. Many offer these at no cost.
Also check out our previous posts on LASIK:
Until about 6 or 7 years ago, I never had to wear glasses. It wasn’t until I began having problems seeing to drive at night that I went for an eye exam as an adult. Millions of people have problems with night vision. But what exactly is it and how is it caused?
“Night vision is the ability to see in low light conditions.” (Wikipedia). Biologically, human eyes can adjust to night vision on their own (to a certain extent). Photoreceptor proteins in the eye must be recharged with active retinal to allow us to see in the dark. The entire process takes about 45 minutes, but most of the adjustment takes place within the first 5 minutes.
There are several technologies that exist to enhance human night vision beyond its natural ability. These include night glasses, low light cameras, and thermal imaging. Not too long ago, night glasses were the only option. Current technology has brought us NVDs (night vision devices). NVDs are usually used by the military, but more and more civilian uses are becoming popular (for example pilots, hunters and drivers of premium vehicles). Perhaps the most well known NVDs are night vision goggles (often featured in military video games and movies). Have you ever wondered why everything looks green through these?
Even at night, the photons that hit the lens at the front of night vision goggles are carrying light of all colors. But when they are converted to electrons, there’s no way to preserve that information. Effectively, the incoming, colored light is turned into black and white. Why, then, don’t night vision goggles look black and white? The phosphors on their screens are deliberately chosen to make green pictures because our eyes are more sensitive to green light. It’s also easier to look at green screens for long periods than to look at black and white ones (that’s why early computer screens tended to be green). Hence, night vision goggles have their characteristic, eerie green glow. (www.explainthatstuff.com)
Poor night vision may be referred to as “nyctalopia” or “night blindness”. Symptoms of night blindness include halos, blurred vision, delayed adaption period between bright and low light, and weak vision in dimmed light. If you are experiencing any ongoing symptoms you should visit an Eye Care Professional and get a dilated eye exam. The doctor may ask you questions about your symptoms, ask you about your medical history, use a slit lamp to examine your eyes, and perform color blindness and visual acuity tests.
If you have poor night vision or night blindness, there are several potential causes. These include…
- Vitamin A or Zinc deficiency
- Retinitis pigmentosa
- Sunlight exposure (“sustained bright sunlight can impair nigh vision for up to 2 days” according to WebMD)
- Complications from LASIK surgery
As a child, my mom would always tell me to turn the light on before reading because reading in dim light would hurt my eyes. I never really believed this fact so I decided to Google it and see who was right. As it turns out this is a common myth. This gave me an idea to explore other eye myths.
Fact: Dim lighting can make your eyes feel fatigued more quickly, but it will not harm your eyesight.
Source: Harvard Medical School
Fact: Eye exercises do not diminish the need for glasses. Your vision relies on the shape of your eyes and the health of your eye tissues, along with other factors such as genetics.
Source: Harvard Medical School
Fact: The eyeglasses worn to correct nearsightedness, farsightedness, astigmatism, or presbyopia will not weaken the eyes any more than they will permanently “cure” these kinds of vision problems. Glasses are simply external optical aid that provide vision to people with blurred vision caused by refractive errors.
Source: Mayo Clinic
Fact: The term “20/20″ means a person has excellent central vision. However, other types of vision, such as side vision, night vision, or color vision, might be imperfect. Some potentially blinding eye disease can take years to develop. During this time, they are harming parts of the inner eye, but the central vision can remain unaffected.
Source: Mayo Clinic
Fact: Sitting to close to a TV will temporarily strain or dry out your eyes, but no permanent damage can be done. Much of the problem can come from the screen, because people staring at them for long periods of time tend not to blink. Some of the strain can be avoided by taking breaks when looking at screens for a long period of time.
Source: ABC News
Fact: There is not enough evidence to support this claim. Keeping a nightlight on in your baby’s room may actually help them learn to focus and develop important eye coordination skills when they are awake.
Fact: Eating carrots along with other foods can help to improve your eye health, but that doesn’t mean eating a bunch of carrots alone will improve your eyesight. Carrots contain a lot of Vitamin A, which is an essential vitamin for sight. However, only a small amount is required for good vision.
Source: Harvard Medical School
Fact: According to the AAO, “as with all medicine, early diagnosis and treatment can help people with their overall health. Just as with a physical, it makes sense to visit an ophthalmologist (Eye M.D.) for a routine eye exam.” You can view the AAO’s recommended intervals for regular eye exams at http://development.aao.org/eyecare/treatment/eye-exams.cfm.
Fact: Only 18 percent of people who are visually impaired are classified as being totally blind and the majority of them can differentiate between light and dark.
Source: American Foundation for the Blind
Fact: “Cataracts are most common among people over 65 years of age; however, cataracts can occur in people who are younger. These cataracts result from conditions such as diabetes, certain medications and other eye problems. In some cases cataracts can be present at birth; these are called congenital cataracts.”
Also check out our past posts on common eye myths:
Originally posted on The VisionHelp Blog:
No … No! Not the Rick James version of Super Freak, though that was the title of Levitt & Dubner’s book that advanced the Freakonomics principle.
The entire audiobook of Think Like A Freak is well worth a listen if you have an aversion to reading, but if you only have two minutes, go to the 2:18:22 point and you’ll hear something special.
Here is the transcription of that clip, from pages 91-92 of the book:
“Trillions of dollars have been spent on worldwide education reforms, usually focused on overhauling the system in some way – smaller classrooms, better curricula, more testing, and so on. But as we noted earlier, the raw material in the education system – the students themselves – are often overlooked. Might there be some small, simple, cheap intervention that could help millions of students?
One in four children, it turns out, has subpar eyesight, while…
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My husband works outdoors every day and wears sunglasses all the time. He was recently shopping for a new pair and was wondering what exactly are the important features in sunwear? Over the past few years we have written several posts about sunglasses (mostly about our children’s sunglasses) but we have never explained what key things to look for in a pair of sunglasses.
First, let’s explore a bit about why sunglasses are important. Ultraviolet light, or UV radiation, is naturally emitted from the sun. The Earth’s atmosphere protects us from some of these rays, but not all of them. UV light has a shorter wavelength and higher energy than visible light.
Although designed to protect the eye, the eyelid’s skin is thin and contains many fragile tissues vulnerable to UV light. Inside the eye, the lens and cornea, both transparent, filter UV rays, but years of UV absorption can damage them. The lens, the eye’s focusing mechanism, can turn yellowish and cataractous. The cornea, the area in front at the outer layer of the eye, admits light and images to the retina. UV damage can cause cancers of the eye, intraocular melanoma, cataracts, macular degeneration, and keratitis (corneal sunburn). skincancer.org
Since people with fair skin and light eyes have less melanin in their bodies they are more susceptible to eye disease and skin cancer than those with dark skin and eyes. Also, people who already have cataracts or macular degeneration should be especially careful in protecting their eyes from UV light.
Wikipedia (which is quickly becoming my favorite website) tells us that sunglasses date back to prehistoric time. Intuit people developed ivory glasses with narrow slits to reduce their exposure to sunlight. In the 12th century people in China wore smoky quartz glasses to protect their eyes from glare. In the 1920’s modern day sunglasses became a commonly found product. Foster Grant “is the original American sunglass brand” (fostergrant.com). The company was the first to mass produce inexpensive sunglasses. Sam Foster began selling these on the beaches of Atlantic City, NJ. At first, sunglasses became popular because of fashion. “In 1937…only about 25% of American wearers needed them to protect their eyes” (Wikipedia). As time went on, however, more and more people began to wear them for protection.
There are a multitude of options for sunglasses in different shapes, sizes, colors and styles. Prices range anywhere from $1 at the local dollar store to hundreds of dollars for brands like Oakley and Maui Jim. When shopping for a pair of sunglasses, no matter your price point, there are a few key features to look for.
- UVA and UVB protection. Look for sunglasses that protect 99% or more of UVA and UVB rays. If they are labeled “UV 400″ or “UV Absorption up to 400nm” it means that they block 100% of UV light.
- Polarization and Anti-Reflective Coating. Polarized lenses reduce the amount of glare from surfaces like car windows, pavement and water.
- Impact Resistant. The FDA requires all sunglass lenses be impact-resistant. If you play sports or wear sunglasses on the job then you should consider special sunglasses designed for sports and safety.
- Size and Shape. When trying on sunglasses, make sure the lenses fit close enough to the face to block stray light but far enough so they don’t touch the eyelashes. Wraparound styles are shaped to keep light from entering around the frames and protect your eyes from all angles.
- Color and Shade. Just because a pair of sunglasses is dark grey does not mean they are a good quality pair of lenses. In fact, purchasing a pair of sunglasses that have inadequate dark lenses can even cause more harm than inadequate light lenses, or no lenses, because they cause the pupil to open wider, which lets in more unfiltered light.
- Distortion Free. To check the quality of a pair of sunglasses, put them on and look at a straight edge. Move your head back and forth and your eyes from side to side. If you see the line wiggle the lenses are probably distorted. You can also take them into your local optical shop and ask them to check the quality of the lenses.
So what options exist in today’s market? Whether you wear prescription glasses or not you can find a variety of choices online and in stores. Here are a few of them…
- Children’s sunglasses (children’s eyes are actually more sensitive to UV light than adult’s so it is very important to protect them from an early age)
- Prescription Sunglasses or Reader Sunglasses
- Prescription glasses with photochromic lenses (gradually change from clear to dark when exposed to UV Light)
- Fit Over sunglasses (go over prescription glasses)
- Clip On sunglasses (clip on to the frames of prescription glasses)
- Flip Up sunglasses (clip on to the frames of prescription glasses and have a hinge so they can be flipped up when not in use)
- Post-mydriatic (given out to patients after a dilation exam)
- Sun Lenses (magnetically attach to prescription glasses)
- Plano Sunglasses (sunglasses that do not correct vision and are meant to be worn on their own)
A few other safety measures can be taken when in the sun, such as wearing a large brimmed hat, sunscreen, and staying out of direct sunlight during the hours of 10 am and 2 pm.
Here are our previous posts on sunglasses
Have you ever wondered what our eyelashes are really for? As you may have guessed, their primary role is to keep debris out of the eye. They also help us sense if an object gets close to our eye (kind of like whiskers do for some animals). Eyelashes develop on humans between the 22nd and 26th week of pregnancy.
Eyelashes are associated with a few diseases and disorders. According to Wikipedia these include
- Madarosis: the loss of eyelashes
- Blepharitis: the irritation of the lid margin, where eyelashes join the eyelid. The eyelids are red and itching, the skin often becomes flaky, and the eyelashes may fall out
- Distichiasis: the abnormal growth of lashes from certain areas of the eyelid
- Trichiasis: ingrown eyelashes
- Eyelashes may become infested with parasitic crab louse.
- An external hordeolum, or stye, is a purulent inflammation of infected eyelash follicles and surrounding sebaceous (Gland of Zeis) and apocrine (Moll’s gland) glands of the lid margin.
- Trichotillomania: a disorder that urges the sufferer to pull out scalp hair, eyelashes, etc.
- Demodex folliculorum (or the demodicid) is a small mite that lives harmlessly in eyelash and other hair follicles, and about 98% of people have these mites living on them. Occasionally they may cause blepharitis.
Many cultures, including the U.S., relate long eyelashes with beauty. There are many ways to achieve longer lashes including mascara, curlers, eye putty, and extensions. Some individuals even get eyelash transplants. In 2009 Allergan began selling LATISSE®, which “is a prostaglandin analog, indicated to treat hypotrichosis of the eyelashes by increasing their growth including length, thickness and darkness” (allergan.com). There are some risks involved with any kind of modification to your natural lashes (check out our past blog on fake eyelashes).
In 2012 scientists from the Georgia Institute of Technology began a research project on eyelash function. The study revealed that the length of mammals eyelashes, no matter what their size, is “invariably one third the length of the animal’s eye”. They also concluded that “the curviness of an eyelash did not affect its function.” The LA Times published an article on the study earlier this year. You can read the entire article at http://www.latimes.com/science/sciencenow/la-sci-sn-eyelash-length-science-20150225-story.html.
If you want more information on eyelash loss and growth, there are several pieces of information listed on WebMD.
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