This week's post is brought to you by the fab little wisdom of The New Scientist's: 'Does Anything Eat wasps and 101 Other Questions'...How the Heck to Bruises work?


We've all had a good few bruises in our lives. I don't know about you, but as I kid I could pinpoint the exact origin and history as each bruise, but as I get older I find that they seem to spontaneously sprout on my body without any memory of them at all - our bodies cheerily working away to heal us when our big busy brains are occupied on other things. (Well, there are certain exceptions, such as thigh-high furniture corners that are impossible to not notice when you bounce off them like a howling pinball. I'm looking at you, bed!)

However you get them, bruises are certainly strange, often transitioning from reds to purples to greenish-yellows. As with most things colour-related, this is down to their changing composition.

Bruises occur when small capillaries (that is, blood vessels) break under the skin in response to pressure. Haemoglobin  in the blood gives the bruise it's reddish purplish colour. noticing that something is wrong, our usual little saviours the white blood cells rush in to help the healing process. to do this, they start to break down the Haemoglobin, which creates various breakdown products that start to change the colour of the bruise. the red lessens as the haemoglobin deteriorates and biliverdin and bilirubin - green and yellow respectively - are created. these sit around until these are in turn cleared and finally the bruise fades.

The curious thing about bruises is that they offer a snapshot into what goes on in our body every day, even before we launch ourselves at furniture. this breakdown of haemoglobin happens all the time in our blood when the red blood cells have grown old and expired. Our white cells will break down these cells, and then the remaining waste bilirubin is taken up to the liver where it is converted for bile - the same substance that digests your food and causes that awful acid taste when you vomit. if you have too much waste bilirubin hanging about in your body, it turns the skin yellowish as jaundice.

You might find, especially as an adult, that you've forgotten how you got a bruise, namely because they can appear a long time after the injury itself. This is down to blood again: often the injury might be sustained deep in the tissues of the afflicted body part. Since bruises are effectively leaked blood, sometimes it can take a while for them to reach the surface, and might even appear some distance away from the original injury.

Our bodies , as ever, continue to be equal parts awesome and a little gross. Just maybe hold off on the research for this one, ok?

Source

'Contusion Confusion' - Does Anything Eat Wasps and 101 Other Questions - New Scientist (via reader submissions from Claire Adams, Frankie Wong and Stewart Lloyd)

Teeth are amazing.

If there's one piece of wisdom that my mum always gave me, it was 'look after your teeth'. they're often one of the first things you notice about a person; you can grin cheerfully with them, sneer with them, grimace with them. They transform the structure of your face and are integral in keeping us well fed and rearing to go. Tooth enamel is the hardest substance in our body and we have created whole mythologies around their loss and regrowth (and many parents have anxiously tried to decide the proper exchange rate between fae and human currencies for the collection of said discarded teeth.) Today I wanted to take a moment to appreciate our gnashers with these 5 strange facts about our teeth.

1. People's Teeth Weren't Always As Bad As You Might Think

People often complain about the 'Hollywood smiles' in historical dramas. "No one would have perfect teeth like that!" They cry, launching their popcorn at Kevin Costner's face  on the screen as 'everything I do' plays in the background. But perhaps things are a little more accurate than you might imagine. While of course dentistry back then was often quite primitive and hygiene was not quite as it is nowadays, the image of black-toothed Dickensian crones as the common denominator isn't quite right, at least for anything before Elizabethan times.

During the reign of Elizabeth 1st sugar was imported from the New World with far greater ease and quantity than had ever previously been experienced. The aristocracy adored the new extravagant substance and were hooked. Sugar, as we all know, causes hellish amounts of tooth decay if unchecked, so it wasn't long before Elizabeth 1st and many of her peers had the stereotypical black teeth and stinking breath that we often associate with historical characters. By the 18thc and the caribbean slave-driven sugar trade, sugar was far more widely available to those of more modest means and the sugar-scarred smiles remained.

Before that, while people wouldn't have access to advanced orthodontic work and fluoride toothpaste, they nevertheless had comparatively healthy, whiter teeth.

2. The Overbite is a Modern Invention

(I, like many modern teenagers, had quite a bit of orthodontic work that lasted a few years. Teeth-straightening via the ol' train track braces were a breeze, my biggest problem was an overbite that made me look not unlike a ferret. Which meant I had to wear this hideous thing for months at a time all the time. Take a good look - that's two big blocks of plastic that interlock to shove your lower jaw forward. I had to eat and sleep with it in: just imagine trying to mash a sandwich between two blunt cubes of plastic that cover pretty much all of your molars. Fun. Admittedly, people have it a lot worse, but the little insult to injury is that 10 or 12 years later my jaw has gradually clicked back to how it used to be as if nothing happened. It doesn't lock up any more (more fun for young me!) but I will be forever cursed to look a little bit like a rodent or one of those snooty weak-chinned caricatures of snobs.
Ah well, at least I can be comforted by the knowledge that my hefty overbite is actually a pretty modern invention.

It's thought that the overbite appeared in western society only some 250 years ago when the knife and fork commonly started to be used together. Previously people would carry knives with them to chop up food, but generally if you wanted to eat you would take hold of one side of your meal and tear off pieces of it with your teeth like you were eating a KFC drumstick. This put more stress on the incisors and your teeth would naturally develop to meet together more like a grazing animal's. Without this, your incisors keep growing and an overbite becomes more prominent.

This trend was noticed by the anthropologist Charles Loring Brace after he had analysed 19,000 skulls from varying time periods. Notably, we can even see this in Richard III's skull when he was recently uninterred.

3. Anaesthesia was accidentally discovered by a dentist

Throughout history many of the most common and painful ailments were due to teeth problems, so it's perhaps no surprise that the field of anesthetics was pioneered by many dentists. One of the most important, and certainly unexpected, developments in anaesthetics was 'discovered' by Horace Wells. One day in 1844 he and his wife sat in on a demonstration of 'laughing gas' (nitrous oxide) displayed by the showman Gardner Colton. While Gardner had briefly studied medicine the show was for pure entertainment due to the amusing antics of anyone under the influence of the gas. During the demonstration one of Gardner's volunteers injured his leg quite badly with a gash as he gamboled around under the influence but seemed completely unaffected. Inspired, Wells chatted to him and found that the man was unaware that he had been injured. Wells got to work and enlisted Colton to help him experiment and the next day Wells bravely decided to have one of his own wisdom teeth extracted under the procedure by an assistant John Riggs. Wells didn't feel a thing and knew he was onto something special.

 The development of the anaesthesia method didn't always go smoothly and required much experimentation and many demonstrations to convince people of its effectiveness. Unfortunately Wells himself came to a rather sad end as he could not quite hack the like of a self-made anaesthesiologist and suffered badly from homesickness and loneliness when he moved from Massachussetts to New York to seek his fortune. He medicated his depression with an over-reliance of ether and chloroform that grew to such heights that he was often in a stupor between waking and dreams and lost all control. On his 33rd birthday he peaked in his drug-induced madness when he threw acid and two women in the street, but fortunately only their clothes were badly damaged. Wells was arrested and, finally growing sober enough to comprehend the depths of his own shame, he overdosed on chloroform and slashed a major artery in his thigh, committing suicide. It was a truly tragic end to a man we owe very much to in the field of inhalation anaesthesia.

4. Children's skulls look like this when they're growing adult teeth.

ARGH!

Awesome.

(Picture by Stefan Schafer)

Humans have twenty baby ('milk') teeth and eventually thirty-two adult teeth on average. Though nowadays with said above orthodontic work many adults carry on as normal with less. (I, for example, have 24 as I had 4 removed as part of getting my braces and for some reason or another at age almost-27 I still haven't grown any wisdom teeth.)

We're not alone in having a  double set - cats and dogs also have baby teeth, but lose them within a few weeks or months. Other animals either have one set (such as baleen whales), multiple sets that constantly shed (like sharks), or have sets that grow continually and need to be worn down (as with many rodents). So why do we have two sets?

Primarily it is believed to come down to skull size: as babies our skulls just aren't big enough for all the big strong teeth we need to last a whole lifetime. Human babies take it even one step back again, being born without any teeth at all. Naturally this makes breast-feeding less of a horror show, but it also is because human babies are so underdeveloped that they're really overly-precocious foetuses. So in the intense period of growing that a small child does, the baby teeth will serve them just fine. When their jaws begin to grow to adult sizes then new teeth will appear, being guided by the original positions of the slots of the baby teeth. Pretty neat!

5. Your tooth can even be used to cure a certain kind of blindness....

It remarkable what medicine can do with a little creative engineering. Check out this video about a Minnesotan woman who , after having her tooth taken out and turned into a lense for her eye, can see again in one eye after being blind for nine years. She tells us in her own words about how many funny looks she gets, but most importantly about how amazing it is to be able to see her grandchildren for the first time.

Sources

-History of sugar

-Qi infocloud: cutlry

-Connecticut History

-22 words - What children's skulls look like as they're about to lose their baby teeth

-Science world why do we have baby teeth?

-The holistic dentist

Why is it that Mike the Chicken could live without a head?

Mike the Headless Chicken

It was the 10th of September in 1945 and Clara and Lloyd Olsen were hungry. Conveniently, they kept chickens and roosters, so Lloyd picked up his favourite axe and wandered out to pick off one unlucky resident. His mother in law was coming to stay and he knew that she loved the neck of the chicken the best of all, so he decided to aim to leave as much of the fowl's neck intact as possible when he made the kill.The rooster he picked was Mike and he swung his axe, lopping off Mike's head in one clean movement. Mike staggered around a bit - as most beheaded birds tend to - and Lloyd wasn't phased.That, he thought, was that.  Until Mike, seemingly unharmed, picked himself up and carried on pecking for food and preening his feathers....

Lloyd, like most of us, was rather stumped. He left Mike be and returned the next morning to find the chicken snuggled up and sleeping peacefully, having tucked his stump under his wing. While many of us would have backed slowly away, probably desperately trying to remember which is the 'right way' to sign out a crucifix, Lloyd instead made a decision: if Mike had so much will to live, then Lloyd would make sure to help him.
From then on Mike became more of a pet. Lloyd found that he could feed the decapitated chicken with an eyedropper, putting grain and water down his neck. Mike thrived, carrying on growing from 2 1/2 lbs to a 'robust' 8lbs and lived for a total of 18 months. The Olsens exhibited Mike at sideshows and had him insured for $10,000. He was featured in the Life and Times Magazine and even achieved a Guinness world record. Tragically, Mike finally died in a motel when he began to choke and Lloyd couldn't clear Mike's open oesophagus quickly enough. With that, the tale of 'Miracle Mike' came to an end.


So how on earth could Mike survive without a head?

Keeping Mike alive

Mike wasn't a miracle in the end, but he was certainly remarkable. When Lloyd brought Mike to the University of Utah in salt lake city, the excited scientists investigated what it was which could keep a chicken alive when it appeared to have no brain at all.
Firstly, Mike had missed bleeding to death due to a clot that had formed in the jugular vein. While Mike's head had indeed been severed the majority of his brain stem and one ear remained on his body. In chickens, the majority of their reflex actions are controlled by the brain stem and so Mike was able to remain quite healthy and would carry on in his basic behavioural functions. For chickens, not being altogether the most intelligent of species, this was enough for Mike to appear completely 'normal' even after his brush with death. To put it scientifically, Mike's central motor generators enabled basic homoeostatic functions to carry on as normal in the absence of a cerebral cortex.

The reason why the brain and brain stem are so seemingly separated his down to chicken anatomy. Dr.Wayne.J.Kuenzel - a poultry physiologist and neurobiologist the the Univeristy of Arkansas - explained this as due to the angle of the Chicken's brain. The skull of a chicken contains two massive openings to the eyes, which means that the brain has to be shoved up into the skull at an angle of 45 degrees. If you cut off the head too high - anything above the eyes or lower beak - and a large portion of the necessary brain can remain intact.

Lobotomised chickens are a grisly but completely natural result of an axe swing gone awry, but some scientists have suggested that it might pose a useful -if macabre - solution to the issues of factory farming. The UK architect student Andrew Ford suggested in 2012 that rearing specifically brain-dead chickens that would be farmed for their meat would be the best way to curb chicken suffering. However this idea, despite its pragmatism, was altogether too grim to be adopted.


Does this mean that other animals can live after decapitation?

As the issues of Mike's biology shows the word 'live' is really a grey area. There are plenty of creatures that share similar reflexive organs that work either in tandem with or elsewhere from the main head, and these can create some freaky results following decapitation.

Some venomous snakes, for example, continue to be aggressive hours after death, though they are the reverse of Miracle Mike: it is the heads that seem to be 'alive', not the bodies.
If you feel like never sleeping again, then feel free to see this in action in the video below.

Despite appearances, the snake is not actually alive following on from its decapitation but its lifelike reactions are again down to the reptile's clever biology. The snake has heat-sensitive pits either side of its face and, when these sense body head, it automatically triggers a threat response and the dead venomous snake still tries to bite you.
As with all these creatures this is no doubt fascinating, but it does raise the question of how far do these animals really think, if so much is simply reflex?

Another creature designed to serve as posthumous nightmare-fuel is the humble octopus. Often after freshly being killed for food, octopus tentacles will continue moving and, on occasion, actively trying to prevent itself from being eaten by clinging onto the bowl it was served in. This is down to another fascinating construction of the central nervous system: in an octopus half the neurons it has are located in the tentacles. The main brain serves to simply give direction and the tentacles are in a fashion ready programmed to carry out that task. When the brain is severed, if the body is fresh enough, the tentacles carry on acting out their most usual tasks automatically. That is: "find food" and "prevent us from becoming food."

In many ways the way human bodies work is similar. While we may think of an action 'food!' our arms and hands, over years of development, can pretty much do what they have to do seemingly unconsciously: you keep hold of the fork, you lift it to your mouth, you chew, you swallow etc. While for us this still involves the main brain-stem (even breathing needs your main brain's input) , for other actions the brain isn't really consulted. For example, if you burn yourself it isn't your brain which causes the flinch, but the nerves in your spinal column reacting automatically and separately in your defence.

Frogs can swim, croak and fight without a brain; headless fruit flies can carry out complex actions as normal; and the hearts of turtles - due to 'pacemaker cells' - still keep beating for over half an hour after death. And of course, the infamous cockroaches can carry on living after decapitation due to a distributed nervous system and efficient breathing mechanism that allows them to function as normal until they naturally starve to death.



Alright, I know that this article has been rather grisly this week, and thank you for sticking with me so far. Please feel free to enjoy Calming Cat for a bit before we get even darker.

Ah, that's better.

Ok, ready?


Even to this day, we're not sure how 'alive' decapitated people are, albeit that this 'life' lasts for no more than a minute

The Guillotine is perhaps the most infamous execution technique that has been in common use throughout history. While beheading had been a form of execution since time immemorial, it could at times be brutally inefficient: Mary Queen of Scots, for example, suffered multiple blows to the neck with a ceremonial sword before she was finally killed. The guillotine on the other hand - being in use since at least 1560 - provided a mechanised manner of execution which was believed to be swift and as painless as possible, while also being dramatic enough to serve as a visible symbol of power. With the method of execution being fairly consistent now, many emerging scientists from as early as 1796 began to wonder seriously about how swift and painless this death really was. Did the decapitated heads maintain any sort of conciousness?

Henri Languille's execution by guillotine

Doctors, for the main part, insisted that the shock of the dropped blade must cause immediate unconsciousness and that actual death came a matter of seconds later due to loss of blood supply to the brain. It was believed that when the heart stops that conciousness can only be retained for a maximum of four seconds if standing, eight if sitting and twelve if lying down, and this largely holds true today.
Still, this knowledge in itself is unsettling. Try counting out four seconds while sitting still. Then eight. Then twelve. A second can be a very long time indeed.

It was common knowledge that decapitated heads twitched and moved their eyes and lips but, like the octopus' tentacles or the snake's bite, these were put down to nothing more than posthumous spasms. But many scientists weren't completely convinced. One Dr.Beaurieux was so determined to get to the bottom of the problem that he enlisted the help of the convict Henri Lenguille to study the doomed man's activities after his execution. This is what he reported:

"Here, then, is what I was able to note immediately after the decapitation: the eyelids and lips of the guillotined man worked in irregularly rhythmic contractions for about five or six seconds. This phenomenon has been remarked by all those finding themselves in the same conditions as myself for observing what happens after the severing of the neck …
I waited for several seconds. The spasmodic movements ceased. The face relaxed, the lids half closed on the eyeballs, leaving only the white of the conjunctiva visible, exactly as in the dying whom we have occasion to see every day in the exercise of our profession, or as in those just dead. It was then that I called in a strong, sharp voice: “Languille!” I saw the eyelids slowly lift up, without any spasmodic contractions –- I insist advisedly on this peculiarity –- but with an even movement, quite distinct and normal, such as happens in everyday life, with people awakened or torn from their thoughts.
Next Languille’s eyes very definitely fixed themselves on mine and the pupils focused themselves. I was not, then, dealing with the sort of vague dull look without any expression, that can be observed any day in dying people to whom one speaks: I was dealing with undeniably living eyes which were looking at me. After several seconds, the eyelids closed again, slowly and evenly, and the head took on the same appearance as it had had before I called out.
It was at that point that I called out again and, once more, without any spasm, slowly, the eyelids lifted and undeniably living eyes fixed themselves on mine with perhaps even more penetration than the first time. The there was a further closing of the eyelids, but now less complete. I attempted the effect of a third call; there was no further movement -– and the eyes took on the glazed look which they have in the dead.
I have just recounted to you with rigorous exactness what I was able to observe. The whole thing had lasted twenty-five to thirty seconds."

While Dr.Beaurieux was convinced, similar experiments have not been quite so successful. For example, in 1836 and in 1879 the murderers Lacenaire and Prunier were asked by scientists to wink after decapitation in order to indicate consciousness, but neither managed to do so. Of course, it is likely that the impact struck them to unconsciousness or - rather understandably - they were too preoccupied with having their freaking head cut off to concentrate. Nevertheless, there was no definite conclusion for post-decapitation conciousness.

Nowadays beheadings are thankfully far, far less commonplace. But the rumours of post-decapitation conciousness remain in more modern examples. In 1989 for example, an army veteran said that when he saw a friend decapitated in a car crash, the severed head showed emotions of shock, followed by terror and grief, its eyes glancing back at the detached body. Indeed, in 2011 Dutch scientists use an electroencephalography machine to observe the brain activity in decapitated mice and showed that, rather than snapping straight to unconsciousness, electrical activity remained at the exact same frequency for nearly four seconds, and occasionally even longer.
Current medical theory puts the potential length of time of conciousness at up to 13 seconds, provided that the decapitating blow didn't knock the victim unconcious and allowing for individual variations due to build, health and the immediate circumstances of decapitation.
"The 13 seconds is the amount of high energy phosphates that the cytochromes in the brain have to keep going without new oxygen and glucose"
Dr.Wright stated: in the end it was always the lack of oxygen and blood to the brain that ended in death. Any movement during or thereafter is more likely to be muscle spasms rather than articulate expressions.


No matter how horrifying the notion of headless life is, it gives us fascinating insight to how our, and animals', bodies and minds work every day.


There is also one little silly silver lining to the tale of Mike the unsettling headless chicken.
Mike's fame lives on through his very own festival, now in it's 17th year. If you head down to Fruita Colarado on May you can take part in a 5k run, a disc golf tournament, wing and peep eating contests, a car show, artisan food booths and live music, all in his 'honour'.
Perhaps it's a testament to the human spirit that we can make a party and a tourist industry out of even the most macabre of subjects. Maybe, given the strangeness of our world, that's not a bad thing at all.

Sources
-Mike the Headless Chicken Official Site
-ModernFarmer.com - Here's why a chicken can live without a head
-Cracked: 6 terrifying creatures that keep going after they're dead.
-Today I found out: cockroaches can live without a head
-Executed Today.com
-All Kinds Of History: Some Experiments with Severed Heads
-The Guillotined Head
-Damn Interesting.com - Decapitation
-Live Science.com can a severed head live?
-European history: Does the head of a guillotined individual remain briefly alive?

Nowadays we don't really think of short (or long) sightedness as any sort of disability.

It's commonplace to the point of near invisibility. CBS statistics state that approximately 61% of the population needed some form of sight or reading aids in 2012 (as compared to 57% in 2001). The number only increases as the population weighs in with an increasingly towards older generations and as our lives become more affixed to our screens and books. 

Take away your glasses and contact lenses, however, and it's soon very clear just how vulnerable you are.

Usually I'm reminded of this when I go to the hairdressers. They sit me down, I take my glasses off and instantly I'm plunged back into a world of vague fuzzy shapes. I put blind trust in what the hairdresser is snipping away at. While we make small talk I look straight ahead and try not to squint, and I try to give friendly eye contact when I can't actually see her eyes. There's always something unsettling in holding a conversation with a face that, for all intents and purposes, has more in common with Slenderman's than something human.

I find it hard not to think how difficult life would be without my glasses when I sit in that chair, and how much they enrich my life.

So how was life like for people before glasses were invented? And who were the people in history who worked to give the precious gift of sight?

 

There is debate about just how developed ancient eye-correction was.

 

 According to the scholar Edward Rosen, the first known reference to a pair of eyeglasses was in 1305 when Friar Giodarno di Rivolta remarked 'It is not yet twenty years since there was found the art of making eyeglasses which make for good vision, one of the best and most necessary the world has.'  However, the inventive use of lenses and the like to correct faulty vision potentially much older.

 

Astriophanes (approx 450-385 bc) mentions plan-convex lenses and globes of water that were used to see, and the Roman Seneca is said to have read through a globe of water. However, the use of these aids were not so widespread as to stop a prominent Roman in 100bc from complaining in a letter that he lamented his poor eyesight preventing him from reading. He instead had to rely on his slave reading out any text for him.

 

While it is not confirmed what its use was, the Nimrud Lens is the oldest known lens found in the world and is dated to somewhere between 4,500-3,500 years old. It's entirely possible that people could have used this to aid them in reading. It is thought that the Romans, Babylonians, Greeks and even Vikings all could create similar lenses of varying quality (thought it is suggested that the vikings instead had these manufactures in the Byzantium empire).

 

The Nimrud Lens

  

Eyeglasses as we now know them were likely created in medieval times.

While the gradual wearing of sight is a common ailment of people as they grow older, it is likely that the increase in reading and scholastic learning in the Medieval period drew more attention and inventiveness to the problem of long-sightedness. In 1289 di'Popozo wrote that "I am so debilita-ted-by age that without the glasses known as spectacles, I would no longer be able to read or write. These have recently been invented for the benefit of poor old people whose sight has become weak"

Monastic populations were often the focus for the development of eyeglasses. For example, in the 14th century, it is thought that Friar Alessandro reverse-engineered earlier sight-aids and transformed them into a useful eyeglass, proceeding to share the invention with the population. This was a significent shift away from the norm of invention: in the times before copyrighting craftsmen endeavoured to keep their methods a secret in order to better profit from them, so Alessandro's act of kindness allowed for a great leap forwards in the technology.

 

Art at the time begins to depict people wearing spectacles and they were gradually associated as a status symbols for learned men, though of course this was dictated to by the shifting fashions of the time.

 

It wasn't until the 16th century that concave lenses were created for the short-sighted rather than the long-sightedness that is a usual symptom of age. Perhaps the most famous customer for these new short-sighted glassed was Pope Leo the 10th, who used to wear them while he was hunting. Sometime between 1760 and 1780 Benjamin Franklin began experimenting with even fusing the two, creating verifocals.

 

While the efficiency of glasses were dependant on the sophistication of glass-making technology, perhaps the biggest design challenge was how on earth to keep them on your head!

 

Many spectacles were designed on a hinge that would perch on the edge of the nose like scissors or could be held up to the face. In the 17th and 18th centuries it was common to have glasses on a stick to hold up opera-style, and ribbons were commonly used to affix glasses more tightly to the face in order to get a better focus from them. In 1781-89 glasses with sliding extension temples were created, but these didn't see widespread use until the 19thc.

Nowadays, the commonest style is through temple bars that hook around the ears but, even so, Opthalmologist Melvin Rueban insisted that these spectacles were 'one of technology's best examples of poor engineering design'.

 Modern glasses designs can be adjusted through heating and which curve around the ear, supported by adjustable nose-pads and springs, though any glasses user could quickly tell you that these are still far from perfect.

 

 

Nowadays, technology has advanced to the point of potentially erasing the need for frames all together.

 

Spectacle frames are and, for the foreseeable future, will continue to be the most popular option for vision correction due to their practicality and relative(!) cheapness. However, we are now lucky enough to have the options of contact lenses and laser eye correction to cure short or long sightedness.

 

Contact lenses were suggested as early as 1845 by Sir John Herschel, but it was F. E Muller who first put them into practice by blowing a glass lens over the eyeball of a man whose lid has been destroyed by cancer. This contact lens was said to have lasted until his death 20 years later. While further experiements and studies commenced, it wasn't until the 1940s that a full variety of contact lenses became available to the public and widely used.

By 1964 some 6 million people in the US wore contact lenses, with 65% of which were female. Given the vulnerability of spectacles to rather severe criticism in fashion, and the close link of traditional female identity with her looks, this is rather unsurprising.

 

 

In the 1970s the development of the excimer laser offered a ground breaking alternative to both spectacles and contact lenses - what if short or long sightedness could actually be cured?

Stephen L Trokel used it to experiement on the eyes of cadavers and then living animals, seeing how their corneas could be altered for the better. In 1988 Trokel was lucky enough to have a willing human participant: a 60-year old woman who was due to have her eye removed due to a malignant melanoma asked if they would like to experiment on her. Trokel's colleague, Marguerite MacDonalD performed the first photorefractive Keratectomy on the lady that year. By the early 1990s the procedure was approved in Canada and the US.

In 1999 the development of wavefront technology allowed doctors to map out a patient's prescription on the unique corneas and by 2002 100% bladeless surgery was finally possible.

Sight correction has come a long way in our history and it can only get better

 

Currently scientists are even on the verge of helping the blind to see.

In 2009, following a work accident, the builder Martin Jones was left blind but, luckily, with one eye still intact. Groundbreaking surgery, carried out by the surgeon Christopher Liu, allowed one of Martin's teeth to act as a replacement lens. While admittedly quite a grisly procedure, it allowed Martin to see his wife after 12 years of blindness. As the tooth is part of Martin's body, there is a far smaller chance of his body rejecting it than if it was made form synthetic materials.

How Martin Jones gained his sight back

Oxford University's smart glasses are designed to help near-blind users by amplifying what little available sight they have.

 The device takes 3d objects and alters the images, making them into bright defined silhouettes.

 One user, Lyn Oliver, was diagnosed with Retinis Pigmentosa in her early 20s which gradually led to extensive vision loss. She relies on her guide dog Jess to navigate, but using the glasses made this significantly easier.

 

“If Jess stops, the glasses can tell me if she’s stopped because there’s a kerb, there’s something on the floor or it’s roadworks, and it’ll give me a sense of which way she may go around the obstacle.
‘If people are stood outside a shop talking, they often go silent when they see me and watch me walk past. But they’ve disappeared as far as I am concerned. Have they moved? Have they gone inside the shop?
“There’s a sudden stress about avoiding them. The glasses help remove this layer of stress and they do it in a way that is natural to the person using them. After taking them off I was missing them." 
Here are the smart glasses in action:

 

Clearly there is still a lot of work to be done but it's amazing how far we have come in giving preserving the most precious of our senses.

Sources

-CBS Statistics

-Is too much TV really bad for your eyes?

-The History of Eyeglasses

-The history of eyeglasses (shopko optical)

-The evolution of eyeglasses

-The early history of eyeglasses - optiboard

-Ancient Wisdom

-Amsterdam's Museum of Spectacles

-The history of laser vision correction

-Blind man see wife for first time after having tooth implanted into his eye.

-Oxford University's smart glasses