OD stands for oculus dexter and indicates the RIGHT eye

OS stands for oculus sinister and indicates the LEFT eye

OU stands for oculus Uterque and indicates BOTH eyes

I just wanted to say THANK YOU TO WHOMEVER ANSWERED THIS QUESTION!! I came here searching for the answer to this same exact question and found this discussion which answered my question perfectly! So once again, thank you thank you thank you!! :-)

Sincerely, Jenna Spier

The third link provided is for an art historian specializing in the history of picture frames.

There is plenty of room, however, for any particular eye or pair of eyes to do whatever they like.

According to Dr. Tan Quach of Adelaide, Australia:

Astigmatism can indeed get worse. the cause of this, whether it be pathological (ie post injury) or hereditary may influence whether or not it worsens.

Typically though, it does get worse with age. i believe it is unlikely that it will revert to normal, however i am unable to obtain clinical evidence of this. there is definitely the chance that it will remain unchanged throughout life.

The good news is, through technological advances, patients with astigmatism can now use the more comfortable, soft contact lens. colour lens are also available. Finally, refractive surgery may also prove benficial for some patients.

According to "Howstuffworks.com":

Most experts agree that reading in low light does not damage your eyes. It can cause eye strain, however, which has a number of unpleasant temporary symptoms and possibly some long-term effects.

When the room light is low, your eye adjusts in several ways. First, the rod and cone cells on the retina begin to produce more light-sensitive chemicals. These light-sensitive chemicals are the first step in detecting the light, converting it to an electrical signal and transmitting that electrical signal to the brain. Second, the iris muscles relax, which causes the opening of your eye, the pupil, to become very large. This allows your eye to collect as much light as possible. Finally, the nerve cells in the retina adapt so that they can work in low light. These three changes take about 20 minutes to 2 hours, but they increase your sensitivity to low light by about 10,000 times.

When you read, your eye must be able to focus an image of the words onto your retina. To do this, the iris, as well as the muscles that control the shape of your lens, must contract to keep the focused image on the retina. If you read in low light, your visual muscles get mixed signals: Relax to collect the most light, but at the same time, contract to maintain the focused image. When that object is poorly lit, focusing becomes even more difficult because the contrast between the words and the page is not as great, which decreases the eye's ability to distinguish visual detail. That ability is called visual acuity. Your eyes have to work harder to separate the words from the page, which strains your eye muscles. Consider this to be strenuous exercise for your eye muscles. So your eye muscles will ache, much as your arm muscles and leg muscles become sore after strenuous exercise.

When your eyes are working this hard for a long period of time, the strain may cause a number of physical effects. Symptoms of eye strain include sore eyeballs, headaches, back and neck aches, drooping eyelids and blurred vision. Because you often don't blink enough when focusing on a single object, you may also experience uncomfortable dryness in your eyes. None of this damages your eyes, and all of it eventually goes away after you stop straining them. Many eye doctors leave it at that, but some note that eye strain may contribute to nearsightedness. Most people who are nearsighted were born that way, but there is evidence that prolonged eye strain can make it worse.

If you are comfortable reading with a flashlight (or other low light) and don't experience any of the above symptoms of eye strain, it's probably fine for you to read this way. It's certainly easier on your eyes to read in good light, however. You can also avoid eye strain when you're reading by blinking frequently and taking a moment to focus on something out the window or across the room every 15 to 30 minutes.

I want to buy a Cartier watch yes its online, I want to find out how can I find if its a fake? This person has givin me the serial NUMBERS so this makes me feel a little better BUT,you can never be to safe.. So I just wanted to know if it a fake before I put out the cash! I'm not even sure if I will get my answer from here, but it don't hurt to try :-) Thanks -N.T.S

ANSWER:

I specialize in buying and selling Cartier watches. I've seen fakes with all the correct marks and a serial number, but that doesn't mean they are legitimate. If the watch was registered by Cartier when it was sold or if it has been sent in to Cartier for service Cartier will be able to verify it is authentic, but be aware that if the watch was not originally sold in North America or was not registered when sold (fairly common) it can still be authentic. Some sellers offer the Cartier quartz model for sale and only state that the watch has a quartz movement, but fail to mention if it has a Cartier quartz movement. If it has a replacement movement in it the watch is technically authentic, but not original and is not worth as much as one with an original or a genuine Cartier replacement movement. The biggest mistake I've seen amateur Cartier buyers make is using the Cartier micro-script signature on the Roman numeral to verify authenticity. Indeed this is a good indicator, but not the best indicator as there were many Cartier watches produced prior to the technology required to make the micro-script possible and not all Cartier watches have Roman numerals for the dial to have the micro-script signature. Furthermore, the micro-script is not always located at the same place and if the dial has been refinished it may not appear at all. Another common problem is actually caused by language differences, i.e. "all original versus "authentic". A watch can be authentic without being all original. Unless someone has owned the watch since it was new and it has never left their sight it is impossible for them to state the watch is "all original" as a part could have been replaced at some point in time -- even without their knowledge. Your best bet is to buy from a reputable seller even if you have to pay slightly more money. -- Cartier_Specialist

Italian Salvino D'Armate of Florence is credited with inventing the first pair of wearable eyeglasses in 1284. It is said a memorial once stood, honoring him, but it no longer exists. However, Egyptian hieroglyphs dating to the first century AD show people using glass sheets as a manner of vision correction.

As early as 700 BC, the Assyrians used polished crystal to magnify objects. Ancient Egypt and Babylon used similar objects and the ancient Romans and Greeks filled glass spheres with water for the same purpose.

Seneca, the Roman philosopher, wrote about filling transparent vessels with water in order to magnify objects seen through them. Emperor Nero, who reigned during Seneca's lifetime, is said to have used the first monocle, an emerald held in front of one eye as a lens to better see at distances.

Sometime between the 11th and 13th centuries, monks used reading stones to help them see the manuscripts they were illuminating. These reading stones were made by cutting glass spheres in half and holding them over the text or artwork needing magnification.

Roger Bacon, the forerunner of modern science, wrote of the magnification properties of lenses in 1262. His observations, based on experiments, were used by later scientists in the burgeoning studies of the natural sciences.

In conjunction with the Age of Enlightenment, during which new ideas about scientific subjects like earth sciences and astronomy were developed, optics became an important topic.

Others, like Alessandro di Spina, were also given credit for the first eyeglasses, and though doubt exists as to the actual inventor, all prototypes were probably invented in Italy late in the thirteenth century. The use of eyeglasses was depicted in several artworks created in the fourteenth and fifteenth centuries, giving credence to the existence of spectacles during this period.

Hyperopia, or farsightedness, and presbyopia, the vision problem that develops with age, were the first eye conditions for which glasses were invented. These armless convex-lensed glasses, called pince-nez, were pinched together to sit on the bridge of the nose. Over the years, various contraptions were used to hold the lenses, from a ribbon attached to the lenses and wrapped around the wearer's head to lorgnettes that held the lenses atop a long handle. Others with attached handles that operated like scissors were called scissors-glasses.

Edward Scarlett of Great Britain invented the first earpieces similar to what are used today.

Lenses for nearsightedness, or myopia, weren't discovered until later, when Nicholas of Cusa is credited with using concave lenses for this condition. In his 1604 paper on optics and astronomy.

German astronomer Johannes Kepler offered a scientifically correct explanation of the effectiveness of concave and convex lenses to correct vision deficits. His treatise formed the basis of today's optical science.

In 1784, almost two centuries after Kepler's writing, Benjamin Franklin invented the first pair of bifocals. Reportedly suffering from both myopia and presbyopia, Franklin was attempting to avoid the aggravation of switching between pairs of glasses to read or to see distant objects. His invention had a frame that held two lens sections together. The idea of cementing these two lenses together was not conceived for another one hundred years.

Since then, the technology for eyeglass lenses and frames has improved, contact lenses have been developed, and lasers are used to correct some vision problems. What was a tremendous mystery centuries ago is now an ordinary part of most people's lives. the the ps3

Some say it was Benjamin Franklin who invented bifocals.
Salvino D'Armate, an Italian, created the first wearable eye glasses in 1824. Benjamin Franklin, and American scientist, invented bifocals in 1784 to avoid having to regularly switch between two pairs of glasses.
no one knows who invented the spactales...they date back as a simple mag. glass in 4 BC
Salvino D'Armate invented the first wearable eyeglasses; however, Egyptian heirogliphics depict people holding sheets of glass to correct vision. Ben Franklin only cut his two pair of eyeglasses in half and put them together to be credited with the first bi-focal.
Salvino D'Armate is credited with making the first workable pair of glasses in 1284. Benjamin Franklin devised a way to make a pair of glasses with bifocal lenses in the mid 1700s.

Polarized Lenses - Protective Eye-wear that reduces glare "Cut the glare. Increase vision. And look cool while you're at it", seems to be the mantra of these highly advantageous eye accessories.

Polarized sunglasses lenses are made to neutralize the effect of glare. A 'glare' is caused when the sun's shining rays reflect off a solid surface or water. A 'glare' is typically horizontally polarized. And the lenses are made of vertical polarizes so Voila! They effectively neutralize the villainous glare! Advantages of Polarized Sunglasses: Polarized sunglasses are specially made for reducing the harmful effects of glare and eye-damaging light. And they are a perfect boon, for all your outdoor activities.

Polarized eye wear For outdoor activities that involves blinding sunlight" Polarized eye wear For outdoor activities that involves blinding sunlight Sports, Golf, Skiing, Fishing, Riding, Mountain Climbing and more.. Polarized lenses are perfect for a whole variety of activities. On the golfing greens, when you're riding, or jogging, or hiking in the wild, or doing anything that involves your being in blinding sunlight. This health eye wear also recommended after eye operation. Not only will you get complete protection from the ubiquitous UV rays and harmful glares, you'll also look totally chilled-out and cool! with our replica sunglasses. So do your eyes a favor and get yourself a pair of these small wonders.

These are best sunglasses in snow that cuts reflective glare.