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Seeing with one eye, why intensity doesn't get half?

Seeing with one eye, why intensity doesn't get half?


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Today I just closed one eye(for finding blind spot), and as usual some of the visual field is lost, but I wonder why is not intensity of light(brightness) reduced to half? Shouldn't it be since our brain is now getting only half impulses?

Does our brain instantly reduces the threshold of rods and cones when one of the eye is closed?


Think of eyes as cameras producing an image at a given framerate. If you have 2 cameras and shut 1 of them off, that doesn't change the amount of light incoming to the other camera.

Your question is one of signal interpretation rather than receiving signals and adding them. Given that the 2 cameras have different perspectives, adding their respective pixels makes no sense. Instead, the dual images (if both cameras are on) are post-processed for spatial reference relevant to perspective.

In the case where a camera is shut off, then the spatial reference becomes a null picture and the post-processing can be skipped.

(For reference, if you took incoming data from both eyes and added them, the result would be an incoherent and largely unusable mess)


Experiment 2

Aim: Effect of intensity on two eyes

Requirement : Two eyes, a dark transparent glass, an object to glance.

Procedure : 1)Sit in a lit room 2)Look at fan with only right eye 3) Look at fan with only left eye through dark glass. 4) Look from both eyes( keep dark glass in front of left eye)

Observation : Brighter in only right eye, darker in only left and medium brightness with both eyes.

Result: Intensity do add when are different. Or more correctly they rather average out.

In your actual experiment, the intensities in two eyes just averaged out, that was mathematicaly equal to single eye.

Theory:

Three principle

1) Brightness is transferred via frequency principle. Greater the intensity of light, greater the frequency of AP transmitted.

2) [Action Potential ][1]

Action Potential has a fixed depolarising potential.

3) Each spatial point, in space, of vision, is represented on a single spatial point in occipital cortex.

Two action potential caused by same image pixel reach their representative point on occipital cortex area 17.

They are then sent to visual associative Area 18 for matching.

“Fusion” of the Visual Images from the Two Eyes

To make the visual perceptions more meaningful, the visual images in the two eyes normally fuse with each other on “corresponding points” of the two retinas. The visual cortex plays an important role in fusion. It was pointed out earlier in the chapter that corresponding points of the two retinas transmit visual signals to different neuronal layers of the lateral geniculate body, and these signals in turn are relayed to parallel neurons in the visual cortex Source: Guyton and Hall, chapter 51.

Same impulses from same spatial point are sent to same interneuron.

The action potential cannot rise further.(Principle 1 above)

This fused signal reaches next neuron for further processing. Intensity is judged.

Same amplitude as of one eye reached, so same intensity was percieved by even two eyes.

If fused signal is of intermediate frequency, intermediate brightness is observed.


Changes in vision associated with brain tumours can include blurred vision - for example, you may find it has become difficult to watch TV or read.

You may get a fleeting loss of vision lasting a few seconds ('greying out') related to changes in your posture, such as suddenly standing up.

Or you may find you have lost part of your field of vision. This could lead to you bumping into objects, or you could feel as if objects or people are suddenly appearing on one side of you.

  • Track your vision changes through BRIAN's quality of life tracker, noting when they are worse or better, any patterns that you see or any changes
  • People often experience more than one symptom before a diagnosis, so make sure you understand what other symptoms a brain tumour can cause
  • Book an appointment with your GP or optician for a check up, and keep a note of any questions that you want to ask
  • Take a look at our page about talking to your doctor for some ideas of what to ask and what to expect.
  • Do you think I could have a brain tumour based on my symptoms?
  • What else could be causing my symptoms (changes in lifestyle, other medical conditions, etc)?
  • How can I manage the symptoms I am experiencing?
  • Do I need to be referred to see somebody else about my concerns?
  • If I need to make another appointment, when should this be made for? Who should I talk to?

3 Answers 3

Your problem pops up regularly. That's because RGB numbers do not properly present perceived luminosity. More confusion is caused by hue-saturation-brightness(or luminosity) presentation of RGB numbers. That's only a math transform. Perceived luminosity doesn't follow only the brightness component, hue and saturation affect very much, too.

If somebody has designed how our sight work, he at least hasn't had any respect on our RGB computer color systems.

The problem is well known and several attempts has been done to present colors in computers so, that the numbers present the peceived values more accurately.

Different software support differently those attempts. In Photoshop we have Lab color mode. GIMP has HCL, which seems to be a polar coordinate version of Lab. Krita puts it further. There's even XYZ, the original vision modelling based predecessor of RGB.

If you want make subjectively as bright colors starting from a set of RGB colors, convert them to Lab in Photoshop and turn off the lightness channel in the channels panel.

It's done here to your example pattern. Test yourself and try to guess where the white spot has vanished.

(beware, this screenshot isn't especially accurate because there's numerous conversions between your original and the attachment)

Do not expect these colors are usable by simply returning back to RGB mode and picking the RGB numbers. Probably many of them are clipped due the limited color range of RGB - they are false onscreen and give another way false results when returning back to RGB mode.

If you put on Gamut warning and proof color display and select for sRGB proof colors, many spots are greyed, which means out of gamut.

(relative rendering in the displayable range)

You can compress the color range to displayable following way:

Now the spots stay quite same after returning to RGB mode:

How much they differ, it depends on how well your system is calibrated.

You should be careful before you extend mathematical intuition on colors. There are just so many false assumptions you can make.

First, you have be a bit careful with your nomenclature. While it is normal to call a RGB triplet a color, it is not. It is a device specific instruction that produces a different color on each device*. Additionally intensity may mean how many photons are emitted per unit of time or how intense humans percieve them.

Second, human vision nor standard RGB colorspaces are not linear. This means that #111111 is not half as bright as #22222 even though the numbers are. The separate channels are independent of each other, or as separate as possible for human vision. This means that #FF0000 is less bright than #FF2200, both physically and perceptully. But the channels dont have the same relative intensity so #FF0000 is not same intensity as #00FF00**. (yes this means that the blue of the sky is way brighter than green vegetation even when the appeaar as bright)

So how do you do this. Well it depends on how accurate you want to be. If possible you would use something like CIE Lab, and rely on your Color management system. If your not that particular then you can use any of tge ballpark polar solutions like HSB or HSL see vikipedia for how to compute these.

But in reality the whole story is quite complicated, we didnt even get started on human white balancing. Which is why you get the blue or gold dress discussion.

*That is unless you have a recently profiled/calibrated device and your imaging system is using a color manager.


The science of sight is progressing, but still dimly understood:

In 1951, when Gen. Douglas MacArthur delivered his famous “old soldiers never die” speech to Congress, he astounded his listeners by removing his glasses to read the manuscript Many Congressmen remembered this bit of heroics longer than the contents of the speech. What better proof that this 71‐year‐old general was not fading away! Perhaps not—but MacArthur's eyesight certainly was. Ophthalmologists who watched the event on television recognized one of the early signs of cataracts—a sudden improvement of near vision in old age.

The actress Sylvia Sidney, who had no trouble reading play scripts, discovered her cataracts when she was arrested for driving down the middle of the highway (she couldn't see the white line). Sportscaster Al DeRogatis found out about his glaucoma while waiting for his daughter to take a routine eye exam. A booklet in the doctor's office describing the symptoms—foggy vision, a colored halo around lights, difficulty in adjusting to darkened rooms—convinced him that he was already a victim. (lie demanded, and got, an immediate diagnosis).

According to some estimates, more than six million Americans, young and old, are visually handicapped to some degree. The most complex organ we have—except for the brain—the human eye is also the most fragile, troublesome and misunderstood. The afflictions that can beset it run into the hundreds. Twenty‐twenty vision (without eyeglasses) is the exception rather than the rule almost half the population wears eyeglasses, and most of those who don't certainly will before they die. Serious eye disorders are becoming increasingly prevalent, largely because more of us live to an age at which the eye, like the rest of the body, begins to falter.

There are about two million blind people in the United States, 17 per cent of whom were either born that way or inherited a blinding disease. Most of the remainder suffer from such disorders as glaucoma, cataracts, infections and retinal degeneration. An even larger number are going blind and don't know it, and it is these hidden cases that can best be helped. If they're lucky, some of them will find out about their trouble in time to save at least part of their sight. “With what we know about eye care today,” says Virginia Boyce, executive director of the National Society for the Prevention of Blindness, “half of all blindness in this country is unnecessary.”

Much of this knowledge lies in medicine's ability to detect eye diseases well in advance of their obvious signs. At the Massachusetts Eye and Ear Infirmary in Boston, for example, Dr. Eliot L. Berson uses an electroretinoscope that measures the minute electrical impulses given off by the retina in much the same way that an electroencephalograph measures brain waves. With this sophisticated diagnostic tool, he can pick up indications of trouble in young children who might otherwise endure years of painless but damaging symptoms, with blindness the probable outcome. For the already afflicted, laser‐beam surgery now adds years of sight by “mending” ruptured blood vessels in the retina. Cryosurgery—the freezing of eye tissue—has made operations on detached retinas a less fearful and more reliable procedure. Even for some legally blind people, medicine now offers restored sight. For the inoperably blind, microelectronics is beginning to take over the role of the seeing‐eye dog and the white cane.

Perhaps as important as these scientific developments is the revolution in attitudes toward the partially blinded whose sight cannot be restored. A generation ago, many of these people were put to work caning chairs in effect, they were taught how to go blind. Today, in more than a hundred low‐vision clinics throughout the country, victims of organic eye disease, many of them elderly, are being taught to use their limited vision more effectively—in many cases, through the use of special lenses or electronic devices even more hopefully, by special training that shows them how better to use what sight remains.

In a sense, the eye is simply a built‐in camera, although far More sophisticated than any camera invented by man. Light striking the eye is bent by the protective window, or cornea, onto the retina—a film that need never be replaced—while a highly adaptable, variable focus lens sharpens the light for fine sec. ng. To regulate the amount of light that the eye can handle at any one time, the iris in front of the lens contracts and expands the pupil, or the “camera's” diaphragm. In bright light, this shutter. is narrowed in darkness, it enlarges. What impinges on the retina, however, is not a replica of what we see, but rather an unprocessed bombardment of light rays. The “developing” is done in the dark room of the brain.

The eye is also a code scrambler, turning the unprocessed picture upside down, for instance, fusing two images into one for stereoscopic vision, breaking up the light particles into primary colors, and mixing these into one or more of the 130 hues of the spectrum. This immensely complex function is performed by the cones—the eight million tiny color receptors that line the retinal palette and divide up the work so that certain cones discriminate specific colors. From this point on. researchers aren't positive as to just what happens, but it is thought that this color‐encoded information is mediated at a deeper level of the retina where the mixing takes place to form the hues that we respond to in the actual world.

Along with their companion segments, the rods, the cones are the cells that give us sight. The rods, however, are color‐blind and since it is believed that the eye evolved under conditions in which night vision was essential for survival, we have about 16 times as many night‐seeing rods as we do day‐seeing cones.

What is not fully understood, however, even by the experts, is how the light that strikes the retina produces the sensation of vision in the brain. Prof. George Wald of Harvard has suggested that it triggers chemical boosters which, in turn, amplify the electrical charge thousands of times before it is picked up by the optic nerve. Another possibility, he thinks, is that the photons of light act as bullets that pass through the outer layer of the retina to reach the “inner” areas where they are processed and sent on to the brain. In any case, what happens in the retina is only the beginning of vision: The eye doesn't tell us what to do with the information it receives or even what it means.

This task is left to the part of the brain known as the visual cortex, which unscrambles the message, further refines the color scheme, “prints” the photograph. turns it right side up and compares it with what's already in the data bank to give us the world we think we see “out there,” In order to do this property, the brain also coordinates the motion of the eyes, keeps the lens focused, works the shutter, operates a range finder (for depth perception) and, when occasion demands, closes the operation down entirely by shutting the eyelids. All this takes about a millionth of a second.

Because the brain retains its information, sometimes long after the message has been decoded, we enjoy the further advantage of instant replay. And because it is often highly selective in what it chooses to perceive—“tuning in” the things that interest us and “tuning out” those that don't—what we see is not always what someone else sees who looks at the same event. “Vision is cortical,” says Dr. Eleanor Faye of the Manhattan Eye, Ear and Throat Hospital. “It's the brain, not the eye, that sees.”

Still, the mind's eye is only as good as the information it receives, and it is little wonder that a process so complex and delicately structured is also subject to breakdown all along the line. Fortunately, most problems are refractive, involving the eyes' failure properly to focus the light rays so that the resultant image falls squarely in the center of the retina. When it doesn't, the rays may come together in front of the retina (myopia) or in back of it (hyperopia, or farsightedness). Eyeglasses correct the focus. The majority of the 100 million people who wear glasses, however, are presbyopic as they get older, the lens loses its elasticity and focuses less precisely. They see well enough at ordinary distances but near vision is difficult and, if they don't have their bifocals, they hold the menu at arm's length. All these disorders can be corrected. If one's sight does deteriorate, even when one wears glasses, the chances are that it will be from one of four major

Cataracts. Afflicting more than 300,000 people a year, cataracts occur when the protein molecules in the lens degenerate to the point at which this part of the eye no longer absorbs light. Doctors don't know why cataracts befall some people—mostly those over 60—and not others but, when they do develop, vision can suddenly “sharpen” at near distance just before the lens gets cloudy. Be suspicious, then, if your eyesight at close range seems to improve in older age.

Until a few years ago, the only remedy for cataracts was removal of the lens, which meant that one might have to get along with a “keyhole” in each eye and a pair of special glasses that do the natural lens's ordinary work. Unavoidably, these glasses also magnified everything half again as big as life. Two innovations now promise to give the cataract patient more normal vision. One of these, developed by Dr. Charles Kelman of the Manhattan Eye, Ear and Throat Hospital, cleans out the degenerated protein without removing the lens capsule. Not suitable for everyone, this walk‐in procedure is done by inserting a tiny needle into the eye that vibrates 90,000 times a second, emulsifying the hard matter which is then siphoned

A more radical procedure is the insertion of a plastic lens to take the place of the diseased one. More than one hundred ophthalmologists now do this operation, which lasts about 40 minutes under a local anesthetic and because the new lens is carefully fitted to the size and curvature of the eyeball, the patient may actually enjoy better sight than he did before he got cataracts!

Glaucoma. Next to cataracts, the most frequent single cause of blindness is glaucoma. Unfortunately, it is least likely to be detected in time for effective treatment since the most common form is only gradually signaled by an almost imperceptible loss of vision. One significant indication is a decrease in side vision. But the symptoms have a way of disappearing for a time and physicians say the only reliable test is examination with a tonometer—instrument that measures the fluid pressure in the eyeball.

By reducing the blood supply to the retina, this elevated pressure gradually destroys the tissue, or “film,” on which the light rays focus their image. Medical science doesn't know what causes this pressure to build up, but it rarely occurs before the age of 35. It is surgically possible, in some cases, to drain off the excess fluid but the usual treatment is to reduce the pressure with drugs.

Corneal disease. Unlike the lens and the vitreous gel. the cornea—the front window of the eye—generally warns of its problems with a good deal of pain. And because it helps the lens gather light, any damage that occurs can interfere with vision (although as a cause of legal blindness, it represents only about 5 per cent of all cases). Infections and injuries can destroy the corneal tissue and, until recently, the most common remedy for this was to substitute a cornea from the eye bank. Such transplants have been 90 per cent successful. However, within the last few months, evidence suggests that viruses carried by the donor eye—undetectable in advance—may be transmitted to the recipient. In at least one case, the result was fatal. Ophthalmologists are now using a spongelike, soft contact lens that seeps drugs onto the eye to minimize pain and heal the damage. Since 1973, Dr. Hernando Cardona of the Columbia Presbyterian Medical Center has been implanting a miniature, mushroom‐shaped, plastic “telescope” in eyes that have severely damaged corneas and lenses. He sometimes grafts skin from the patient's mouth to form a false cornea with which he anchors his Teflon “telescope.” Many of his patients, who went for years without seeing anything but shadows or light and dark.

Retinal diseases. Having tackled the cornea, lens and the vitreous gel with encouraging. if not always awesome, success, eye surgeons are now turning to the retina itself. where a third of all blindness originates. If the macula, or the central area, degenerates, as a consequence of age or a number of other causes. the retina becomes scarred and the high ‐ resolution, “bull's‐eye” image we normally see becomes dim and fuzzy. or is missing entirely. In contrast, the outer edges of the retina can fail without loss of central acuity. Dr. Berson examined a man not long ago who tested 20‐20 on the eye chart—perfect vision by ordinary definition—but who couldn't find his way out of the room. His side vision had all but disappeared.

Unfortunately, retinal disorders are the most intractable and least understood. Some. like retinitis pigmentosa—also known as night blindness—are Inherited and there isn't much that can be done to check their course. Other forms are especially common among the elderly, although ophthalmologists don't think that this is necessarily a result of the aging process. Says Dr. Elmer J. Ballantine, director of clinical studies at the National Eye Institute: “There are too many old people with virtually no eye problems to let us explain retinal disease on the basis of age alone, and there are young people, who do have them.”

One of the more common of such ailments, Dr. Ballantine points out—diabetic retinopathy — shows promise of responding to a wholly new treatment. Using a laser beam that involves no surgical incision, ophthalmologists now treat these damaged or abnormal blood vessels by “spot welding,” a technique that takes only a few minutes. How effective or enduring the treatment may be, however, has not yet been established.

Even with the best treatment available, however, a person with retinal blindness can't always be helped. For many of these cases, science is providing substitute vision. converting a world of darkness into new forms of touch and sound. Andrew Potok, a, 43 ‐ year ‐ old, Polish ‐ born American citizen is a good example of someone who is able to “see” in spite of his encroaching blindness. The victim of retinitis pigmentosa, he gave up his carer as an artist a few years ago and entered a Massachusetts institution for the blind. While learning Braille, and being taught how to properly swing and tap his white cane, Potok heard of a new program at Boston University's Vision Rehabilitation Clinic. Here, patients were instructed in the use of several ingenious devices that increase even mini,mal vision.

Potok transferred to the clinic and he now goes about in darkness with a pair of binoculars developed by the Army for night combat. Manufactured by I.T.T., this Nightscope takes a minute source of illumination—starlight or a street lamp, for instance—converts it into electrical en ergy, magnifies it by means of a lens and lights up nighttime images onto a miniature television screen built into the instrument. With this device, Potok can, in some respects, see better at night than the average‐sighted person under the same conditions.

For reading, he employs closed‐circuit television. A book or newsprint placed under a camera is transmitted—greatly enlarged—onto the screen of his set. A folding cane, which he carries on his trips from his home in Vermont to Boston each week, provides help in emergencies.

If things get worse, as they frequently do when the disease progresses, Potok can look forward to a number of other prosthetic aids. With the Optacon, a portable reading device, he will be able to pass a small, hand‐held camera over the line of print and feel the words pass through his fingers as tiny pins vibrate in the shapes of letters. A similar instrument, the Visotoner, uses photocells that are triggered by differences in the shading in the print words are converted into audible tones which the user translates into meaningful prose.

For getting about, Potok may want to consider the Pathsounder, a radar cane developed at M.I.T. that beeps no‐go warnings as it bounces laser beams off surrounding obstacles. Or he can try out the ultrasonic spectacles in vented by New Zealander Leslie Kay. The frames of these spectacles send sound waves onto the surrounding terrain very much in the way that sonar is used to detect objects under water. The reflected waves probe the immediate environment and map its features by converting the sonic signals into musical tones, which are played in miniature earphones mounted on the spectacles. Kay, who says he got the idea from studying the navigational system of bats, also provides a bifocal model—one sensor beam “looks” down, another “looks” straight ahead.

If Potok would rather be tickled than hear musical tones, a miniaturized, solidstate TV camera, mounted on eyeglass frames, will “picture” the environment through an array of tactile stimulators. worn around the abdomen. Still experimental, such types of optical radar have an advantage over the laser cane in that they “see” a wider field of vision.

Probably the boldest work in substitute sight, however, is being carried out by researchers at the Universities of Utah and Western Ontario under grants from the National Institutes of Health. Drs. William H. Dobelle, Michael L. Mladejovsky and John P. Girvin propose to install tiny cameras, about the size of a bean, in artificial glass eyes. These are connected to minicomputers mounted on a pair of spectacles here, the transmitted “pictures” are coded and sent on to the brain via electrodes implanted beneath the skull. This instrument endeavors to do what the normal eye itself does—use electrical energy to produce a visual image in the “seeing” part of the cortex. The resulting picture would be patterned like a newspaper photograph, which is made up of various shades of dots.

Although this project, too, is still in the experimental stage, critics already question both the practicability and safety of such an instrument. The cost would undoubtedly be high, and not many blind people could afford to have their own built‐in cable TV. More important is the possible effect of all that electricity being fired into the brain through 64 electrodes.

Even the more workable aids have their drawbacks. Only a few Nightscopes will be manufactured this year for the 50,000 people who might be able to use them moreover, they have a distressing habit of suddenly turning themselves off when exposed to very bright light—an automobile headlight, for instance. The laser cane, in its present state of development, doesn't give a quick enough warning, according to blind people who have tried it. Users of Visotoners and tactile stimulators must be taught how to translate the instruments' patois into comprehensible language — not although it can be done.

Even if the visible world can be converted into different modes of sense perception—if it can be made to talk to us or touch us, guide us or read to us—this is not vision as most of us know it. The real breakthrough in dealing with blindness, scientists think, will come only as we learn more about the physiology of the eye itself and what actually happens when something goes wrong. At the University of California's Jules Stein Institute, Drs. Richard Young and Dean Bok have been studying the visual cells of the retina—the rods and cones—with an electron microscope. By staining protein molecules with radioactive isotopes, they can follow the progress of these building blocks as they move from birth to death. What they have discovered is that the rod segments break off at the tip as new segments are formed at the base. It is as though a stack of poker chips were continually being replenished by adding a chip at the bottom of the stack and removing a chip at the top. The question: What happens to the sloughed‐off chip?

In normally functioning eyes, Young and Bok found, these discarded cell parts are “scavenged” by enzymes which return them to the bloodstream. But in the most common type of retinal blindness—macular degeneration, which destroys central vision —these segments are not removed they clutter up the retina until sight becomes difficult or impossible. Since there is no surgical procedure that will correct this condition, it becomes important to know just what causes this failure of the retina to renew itself properly.

Using their poker chips daringly, Young and Bok are betting on two hypotheses. One posits a chemical breakdown in the scavenger cells, in which case there might be a nutritional basis for this type of blindness. A more frightening, but manageable, possibility is the effect of too much exposure to light. We have long known that looking at the sun directly burns the retina, and that even suntan lamps can be harmful. Where the eye is already failing, the researchers suggest, one's tolerance for light may decrease.

Following this line of thought, Dr. Berson has raised the ante in an admittedly wild card game. With retinitis pigmentosa, he thinks ordinary illumination causes the retina to become “hyperfunctional” —it works too hard and uses up the chemicals necessary for vision, which is pretty much what happens when a camera film is overexposed. As director of the Berman Gund Laboratory, he is currently testing this notion by fitting one eye of a group of RP patients with an opaque contact lens. These people will wear the lens for five to 10 years, after which the two eyes will be compared. If damage in the deprived eye has slowed down, it is a reasonable assumption that light is the villain.

At the National Eye Institute's Laboratory of Vision Research, Dr. Toichiro Kuwabara and his colleagues are trying to discover at just what point this photostimulus might overpower the retina and cause damage. Their findings, so far, are not exactly reassuring to sun‐worshipers and devotees of the psychede lic discotheque. In one experiment, rhesus monkeys were exposed to continuous flashes from an electronic strobe light. “All exposed retinas began to show pathological changes in their outer segments starting on the second day,” the laboratory's report states. “These changes were found to stay in the retina for a long period of time.” Disconcerting, too, was the fact that they were identical to those found in diseased human retinas.

On the chance that this might be unique to monkeys, Kuwabara and his team repeated the experiment by exposing rats to bright fluorescent lamps. After a week of consistent or intermittent exposure using two test groups, the animals were examined. “Pathological changes” were, indeed. present. All the rats had gone blind! “There isn't the slightest clinical evidonce yet that this would happen to the human eye under the same conditions,” says Dr. Paul J. Oɻrien, who worked on the experiment. “Just the same I wear sunglasses just about everywhere I go.” Dr. Oɻrien thinks the possibility of risk is present for people in the theater or television who are exposed for lengthy periods to high intensity lamps. “If I were Johnny Carson,” he adds, “Iɽ make sure I had a good ophthalmologist.”

Dr. David Cogan, who was chairman of Harvard Medical School's department of ophthalmology until 1968 and now does research at the Eye Institute, contends that illuminating engineers and manufacturers have oversold the American people on the need for bright lights. Some years ago, one company threatened to sue him when he challenged its “Better Light Better Sight” campaign in the press. “Better light doesn't necessarily mean more light,” Dr. Cogan argued. “It may mean less.” Anything over 20 footcandles, he believes, is probably excessive and he keeps his own laboratory not much brighter than a dimly lit restaurant. “I can see fine,” he says, noting that increased visual acuity stops at 10 footcandles.

Last year, at a conference called by the General Services Administration to deal with the energy problem, Dr. Cogan tried to persuade Government officials to adopt a more conservative lighting policy and save millions of dollars into the bargain. Although a report of this conference with his recommendations was duly issued, he notes that most Government offices around the country still burn brightly.

That bright lights are essential is just one of the misconceptions people have about their eyes and vision. Recently, thanks to a nutritional fad spurred by the late Adelle Davis, many Americans have taken to vitamin A as an ocular cure‐all. Its importance in vision is one of the discoveries that earned Professor Wald a Nobel prize in physiology and, in a rare form of retinitis pigmentosa, it cures the disease. For most people, however, too much vitamin A can worsen the eye condition in any case, the liver normally stores about a two‐year supply, and few of us are in danger of running out.

Another prevalent belief is that exercising the eyes will enable us to see better. Although some people still use the Bates method of eye exercises, popularized by the late Dr. William Horatio Bates in his book, “Perfect Sight Without Glasses,” there is no evidence, says Dr. Donald Kupfer, director of the Eye Institute, that it does any good. When scientists at Johns Hopkins University evaluated the results of eye exercises on 103 cases of myopia, not one showed any improvement. (Cross‐ and wall‐eyes, however, can be helped by special “orthoptic” exercises that get them to work together as a pair.)

Such exercises reflect, of course, the intense and widespread concern for correcting defective eyesight. And the scientific progress in the field can evoke only gratitude. However, says Dr. Eleanor Faye, who directs the lowvision clinic at The Lighthouse, one must not overlook the current importance of creating a new psychological attitude toward loss of sight. Rather than stress the defect, Dr. Faye wants to know how well people use what vision they have. She thinks, too, that acuity figures (as measured by the eye chart) are often meaningless with children especially, such figures become a self‐fulfilling prophecy and, in her view, a more useful measure would be a test of visual efficiency. Psychologically, she says, the important thing is not how well you see but how well you get along.

If this is true, how does the man or woman with failing eyesight become more efficient in seeing? One approach is simply to use residual vision as much as possible. Favoring a damaged eye doesn't help it may, in fact, result in “psychological” blindness. Another method is to train the eye by creating new perceptual experiences. We know, for instance, that “seeing” is not an inborn trait but a learned behavior. Visual objects are only gradually built up into meaningful “things,” and in human beings this process isn't fully complete until about the age of 16. People who have been blind for long periods of time, and whose sight is restored, must learn to see all over again. A study of several such cases in Italy revealed that the most common reaction was shock, followed by depression and even a retreat into blindness. Benedetto Strampelli, the surgeon who performed the operations, concluded that the patients who were most successful in regaining sight were those who could best “tune in” the world psychologically and put it together again.

Experiments in this country provide at least preliminary indications that “selecting what to see” also works for people with partial, or damaged, vision. A few years ago at the Tennessee School for the Blind, Dr. Natalie Barraga undertook a program of visual stimulation among children whose poor eyesight resulted from brain damage. By introducing a variety of challenging visual patterns, she induced them to see more—and better—than they thought possible, an encouraging departure from the practice in some schools where the child's eyes are bandaged to prevent his using them at all. Results were impressive. After eight weeks of training, discrimination—the ability to distinguish different objects — went up more than 10 points on a standardized test, although acuity remained the same. One pupil, who at first could recognize only a few letters. was reading near the second‐grade level at the end of the experiment

Dr. Faye thinks that most low‐vision patients give up too soon. Eighty‐five per cent of those who come to The Lighthouse, she says, are aided to some degree as magnifiers help the patient “see around his scars” and the memory is trained to fill in the visual gaps. When sight is impaired, she points out, the greatest damage is not necessarily to the eye but to the ego and this is something that can be strengthened. So whether we are having trouble with the small print or the big picture, the prospects are better for all of us. We need not think of ourselves as blind and, in so doing, become blind. ■


Seeing with one eye, why intensity doesn't get half? - Biology

I watched a documentary on hiccups where doctors applied pressure to the vagus nerve to stop chronic hiccups. Anytime I hiccup, I press firmly on my throat an inch above the collarbone area and it stops immediately. I haven't hiccuped more than twice in a row in over 15 years. This works for most of my family and friends, but my husband can't tolerate the gag/lump in the throat feeling the pressure causes.

Do you mind sharing exactly where this point is located and what sort of pressure should be applied? Thank you.

I think it depends on personal anatomy a bit - almost everyone I show this to takes a few attempts before finding the right spot for them - but I press 2 finger widths above my collarbones (I'm female). It will feel like a lump in the back of your throat. Hold it through the duration of when your next hiccup would be and if you don't hiccup, it's worked.

This 1 lb Early Girl tomato was delicious! An especially cold spring (Zone 10b) gave me quite a few double tomatoes this year.

Aren’t those called twomatoes?

Hmmm. Thats what early girls look like? Im starting to think mine were mislabeled. I mean my "sweet bell pepper" seeds turned out to be jalepeño.

Normal Early Girls are more globe/round shape and about 1/3 - 1/2 this size. These are all double/twin/fasciated tomatoes where parts of the flower doubled and grew two tomatoes together.

That must have been a surprise when your bell peppers never got bigger.

[OFFER] Box of Salty Snacks [US] to [US]

Cheez-It Extra Toasty - so, so delicious.

It's a living thing

Honeysuckle is an invasive vine, not a bush. This show is such bullshit, I wish jeopardy would hostilly take over the timeslot.

Not all honeysuckles varieties are vining. Some are bush or shrub types.

What are some things that are normal in the US but that the rest of the world finds weird?

I personally find it weird when I read certain US English words. They tend to shorten words or phrases to the point where I actually need to think about what they’re supposed to mean. I definitely double take when I see certain words being used on Reddit sometimes

Example: ped-xing for pedestrian crossing signage, or using slaw to describe coleslaw.

Coleslaw is technically cabbage slaw (coleslaw comes from the Dutch word koolsla - kool means cabbage and sla is for salad), so just slaw is other crunchy vegetables instead of cabbage.

[Offer] Spider plant babies galore. US only

I would absolutely adore a spider plant! This is such a nice offer - I have a garden and a few air plants in my home, but would love to have more green inside the house.

11 weeks in with dr. Tsang

So would you with 100% certainty say your improvements are not placebo, but definitely caused by the therapy?

I think there should be a consideration that while it's not a placebo effect, symptoms are highly correlated with stress. Receiving treatment often reduces stress because it provides hope where there was none before. Symptoms are often cyclical as well, so this could also be a coincidence. Or, the treatment is working. I'm extremely reluctant to make any conclusions until there is more study data, but it's still interesting to read about people's experiences with various treatments.

Do you tip budtenders?

I do - 5%. A long time ago, I used to tip closer to 15% when it was medical only and you might spend an hour smelling and chatting about all the strains they had. Nowadays, it feels more like ordering fast food off a menu.


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There's an angel and he's shaped like you by janeives

Fandoms: IT (2017), IT - Stephen King
Summary

"Guess I owe you one, huh?" Richie chuckles.

Across the table, the boy blinks at him with those dark eyes, slow and calculated like a cat. For a moment Richie is struck with the terrible fear that he's going to end up in shreds and spatters of gore, too, but then the boy simply shrugs his narrow shoulders, digging his spoon back into the bowl and helping himself to another mouthful of Froot Loops. In the yellow kitchen light Richie catches the remnants of blood on his chin.

"I'll take that as a yes."

Or: Richie, on the cusp of fifteen, knows he should be worrying about kissing girls and sneaking out and keeping his grades up just enough to warrant fewer trips to the principal’s office. ‘Harboring a runaway half-vampire in my bedroom in exchange for saving my life’ was never supposed on that list. Richie still isn’t sure it should be.


The Science Behind The Colors We See

Does the color of an object come from the element it's made of? originally appeared on Quora - the knowledge sharing network where compelling questions are answered by people with unique insights.

Answer by Inna Vishik, physicist, on Quora:

If we have the entire electromagnetic spectrum at our disposal, yes, we can determine the elemental composition of any substance based on the emission spectrum of the elements. But we would need to vaporize the material first because the emission spectrum of elements changes when it bonds with other elements in molecules, solids, and liquids.

If we confine ourselves to the visible portion of the electromagnetic spectrum, and ignore the brain's role in color perception (see: recent blue/black vs gold/white dress controversy) an object looks a certain color because:

  • It absorbs some wavelengths of light more than others (e.g. something looks red because it absorbs all the other colors).
  • It reflects certain wavelengths of light more than others (e.g. something looks red because it reflects red most readily into our eyes.)(or, if we want to explain photonic phenomena which give opal and butterfly wings their color, we need to specify that it reflects certain wavelengths in a specific direction).

Let's take the color orange to illustrate that this color can arise in many ways.

  • A neon lamp appears to be a specific shade of orange because of transitions between energy levels in neon atoms which fall in the red-orange-yellow region of the spectrum. This is an example of emission causing a specific color, and it is the simplest case to analyze because it only involves unbonded atoms.
  • Copper appears orangey-red because there is strong absorption of green, blue, and violet owing to the band structure of the material. When elements are bound together in a solid, the apparent color may be different than the isolated atom. In a solid or liquid, instead of discrete atomic energy levels, one has bands which effectively form a continuum of energy levels electrons can occupy. For copper specifically, the relevant portion of the electronic band structure consists of a band deriving from 3d electrons which occupies a narrow energy range and another band originating from 4s electrons which occupies a broader range. Absorption of light is accompanied by excitations of electrons from occupied to unoccupied energy levels. The 3d band has a high density-of-states and it is all occupied, so there are many opportunities for absorption originating from this band, and the threshold for this absorption happens to correspond to green light (so everything more energetic than green is absorbed). Note that copper that is not in a solid will not look orange if you incinerate pure copper (don't do this at home), you will get a green flame (source: WebElements Periodic Table ).
  • In some parts of the world, the soil looks orange because of a high iron content, specifically iron oxide (Fe2O3) a.k.a. rust. Iron oxide is an insulator with a band gap of 2.2 eV (563 nm), which means it should be transparent to oranges and reds, which wouldn't cause a red color (which is the reason that some Fe2O3 doesn't look red at all see Hematite for examples of the orange kind and the not orange kind). However, there are impurity states in the band gap which yield an absorption spectrum consistent with an orange color (see: Page on geochemsoc.org )
  • Tannin , the molecule that gives redwood trees their orange color and red wine its color (and taste), is made of different elements than rust. This illustrates that the color itself, especially if we only consider visible light and only use our eyes as a spectrometer, does not necessarily imply a certain elemental composition. A specific molecule has a certain absorption spectrum because of its molecular bonding structure. This structure isn't quite a continuum like a solid, but there are more energy levels available than in a lone atom. As with solids, the 'color' of a molecule may be different than the 'color' of the consistent atoms.

​So to summarize, the colors of objects ultimately come from their elemental composition. But many different elements can produce the same visible color because 1) the visible part of the spectrum is a small portion of their color and 2) the specific way that an element bonds with others makes a difference. See also: How Animals Hacked The Rainbow And Got Stumped On Blue

This question originally appeared on Quora - the knowledge sharing network where compelling questions are answered by people with unique insights. You can follow Quora on Twitter, Facebook, and Google+. More questions:​


What the Type of Bird You See Might Signify

Black birds (crows, ravens, blackbirds)

Black birds are most often associated with death. They are often believed to bring messages from our dead loved ones.

Odin, a Norse God, had two ravens who flew all over the world then returned to whisper what they&aposd seen into his ears.

White birds (doves, egrets, etc.)

Like black birds, white birds are often associated with ghosts, holy spirits, and the afterlife.

Doves are seen by many as symbols of peace or faith.

Owls are often associated with wisdom, knowledge, and insight. They&aposre also sometimes associated with female power and fertility.

Athena, the Greek goddess of wisdom, was always pictured with an owl.

Predatory birds (hawks, falcons, owls, eagles, etc.)

Victory, strength, power, domination, perspective.

Many cultures associate predatory birds with war.

Scavengers (vultures, crows, etc.)

Tenacity, patience, observation, timing.

Most people know that scavengers linger near dead bodies.

Songbirds (finches, sparrows, starlings, etc.)

Domesticity, imprisonment, freedom, cheerfulness.

Miners used to take canaries down into mine shafts as an early warning system for lack of oxygen.

Hummingbirds

Lightheartedness, diligence, the importance of small things.

Aztecs saw them as messengers from the gods and ancestors. They were good luck symbols.

A flock of starlings in a murmuration: What does it mean? These flying patterns are more akin to physics than biology, but scientists still don&apost know how the birds can do it!


My Experience w/ Profractional & Why I Keep Going Back

I’ve gone through skin issues my entire life. As soon as I hit puberty, my skin was pretty much f*cked. Luckily, I’ve gone down a path that has worked for my skin and it continues to improve. If this is your first time reading any of my skincare posts, I definitely recommend reading previous posts. Here you can read about my experience on accutane about 4 years ago. Then I also share a post about my normal skincare routine and the lasers and treatments I do regularly, including a quick breakdown about my first profractional experience.

The first time I did the Sciton profractional laser, I only did it on part of my face and I didn’t share a ton of my experience in that post. About a year later, I decided it was time to go through the process again, but this time on my entire face. And today I wanted to tell you about the full process, why it sucks, but also why I can’t wait to do it again. I strongly believe in this laser treatment and after doing it only 2 times, I’ve already seen a huge difference in my skin. But before I get into that, let’s break it all down!

What The F*ck Is Profractional?!

A profractional laser treatment is laser that resurfaces the skin to help minimize wrinkles and pigmentation and helps improve the skins tone and texture. It’s great for treating scars, wrinkles, fine lines and sun damage such as skin discoloration. The profractional laser penetrates deep into the skin, removing the top layer. This triggers the body’s natural response to heal wounds, which in turn stimulates new collagen and elastin production leaving you with smoother, softer, more even skin. And even after the skin has healed in a week or so, it continues to produce new collagen and just gets better with time, up to 6 months after the treatment!

What Is The Treatment and Recovery Like?

The day of the treatment, your esthetician will give you a topical numbing cream about an hour before. I’ve heard from others that they don’t think the profractional treatment is painful, but I DO NOT feel that way. The first time I did profractional, I was quite surprised how painful it was and it took me about a year to get the balls to go back and do it again. That being said, I contacted a friend who is a nurse and she was able to give me a nerve block in my face to help with the pain the second time around. So not only did I have numbing cream, but I also had a nerve block where I could barely feel around my mouth and cheeks which definitely helped. Let me tell you, I looked realllll cute slobbering my way through the treatment.

Depending on the areas your esthetician treats and treatment settings, it can take 15 to 30 minutes. I think my treatment took about 20 minutes for my entire face. And yes, it was painful even with the numbing and nerve block. There’s just no getting around it if your esthetician is going deep with the treatment settings.

After the treatment, the healing process is pretty rapid compared to other treatments such as chemical peels. With chemical peels, it just gets worse with time before it gets better, but with profractional, it gets better each day. Throughout the first day of treatment, the skin is swollen, red, and may bleed. This is by far the worst day because it’s uncomfortable and feels like you just have a huge open wound. You won’t want to leave the house and I recommend sleeping with a towel on your pillow because your face will be oozing a bit. Right away, my esthetician applied Venus Biocel which has a similar feel to petroleum jelly but has anti-inflammatory ingredients to help the healing process. For about 5 days, I used this Venus Biocel every few hours, as soon as my skin became dry. The whole point is to keep it moisturized so it can heal faster. By day 5, I was using Venus Post Treatment Recovery Kit which includes Renewal Cleanser, Stem Cell Therapy Serum, Stem Cell Recovery Complex, and Stem Cell Therapy Accelerator and I used that for about a week. These products are incredibly helpful when it comes to the healing process and speeding it up. I didn’t use these products the first time I did profractional and I definitely noticed a difference with the healing!

After the first day where you’re a bit uncomfortable, the next morning is a little easier after you wash your face and remove the excess blood. I was DEFINITELY still swollen on the second day but the skin doesn’t feel like an open wound by then. Below is a day by day photo collage of the healing process. Day 1, Day 2, Day 3, Day 4, Day 5, then Day 6 with light makeup on. By Day 3, I was able to put on makeup and go out in public even though I was still brownish-red. Luckily, I don’t give AF so I don’t mind being in public, but if you get embarrassed easily, you may want to stay in until Day 4 when makeup can really cover up some of the lines from the laser and the redness.

What Have You Noticed The Most From Profractional?

When you get to about day 3, you feel like your skin may never heal…even though it’s only been 3 days. I definitely recommend doing day by day photos because this was a great reminder that my skin was healing much faster than I thought. After the first week, I instantly noticed the fine lines around my mouth and some of the icepick scars on my cheeks had reduced or almost disappeared. And many of the dark spots on my forehead that pop up as soon as I hit the sunlight had completely disappeared. After your treatment, your skin looks and feels like you’ve slept on sandpaper. And even after your skin has healed and looks normal again, you can still see some of the sandpaper look if you see the skin close up. It’s been a couple months since I did my last treatment and the skin still looks a bit texturized which means it’s still producing new collagen and rebuilding. Like I said above, the skin continue to heal and rebuild new collagen for up to 6 months so it’s continually improving!

I’m doing profractional treatments for 3 reasons:

  1. To keep my skin looking younger and smoother with time (because genetics aren’t doing it for me)
  2. To improve my acne scarring from the cystic acne I went through before accutane
  3. To improve fine lines and wrinkles

And even though I think this treatment is painful and it’s a bit of a pain in the ass to have your life at a standstill for a couple days, I THINK IT IS ABSOLUTELY WORTH IT. I plan on doing it every 6 months which means I’ll be doing it again in the spring and I’m so excited to see what my third experience looks like! These photos below are about 4 or 5 years apart. The first one is before I started accutane and the second one was taken just a few weeks ago and I couldn’t be happier with the difference. My skin is smoother, softer and the scars are continually getting better with time!

How Much Does Profractional Cost?

Depending on the size of the treatment area, profractional can cost anywhere $500-$1800 and I’m sure it can be more expensive depending on the area you are in.

At the end of the day, you have to find an esthetician you trust and who knows what they are doing. I’ve gone to Shawn Haviland (Cherry Hills Facial Aesthetics 720-459-7960) for a few years now and I could not be more thankful to have found her. If you are not in the Denver area and you are trying to find an esthetician near you, she recommends finding a technician that has state required laser training in addition to training from Sciton along with at least 3 years experience. I found my esthetician by simply asking a friend who had beautiful skin who she went to. Word of mouth can be the most helpful sometimes. But if you are in the Denver area, CALL SHAWN and prepare to have your skin and life changed! She even offers 50% off your first profractional laser if you mention that I sent you!!

Because of this laser, my skin has become more even, smoother and many of the pigmentation issues I deal with have completely gone away! I remember years ago when I was dealing with cystic acne just wishing and praying that I could walk outside without makeup on and feel confident and I am finally to that point! But it took hard f*cking work. I couldn’t just go the hippy, paleo, organic way. Yes, I had to work on my diet and I had to drink more water than I knew possible, but I also had to turn to modern medicine and treatments to truly see a difference. And I’m so glad I went that route.

If you have any questions, feel free to leave them below!! I really hope this post helps you with your own skin care journey in some way!


The ones you can not see

When I was younger, I was admitted to a psych ward. I was very depressed at that time, and my mother convinced herself, that it would make me feel better. Upon my arrival, I was greeted by a middle aged woman. My mom had to sign a bunch of papers, and after that they took me into the bathroom. I had to strip down, so the staff could make sure I didn't bring anything in.

After this long process, they took me to my room. The room was very dull, grey walls, and a bared window. They let me settle in for ten minutes, then I had to go to the great room. I met some people, some where just like me, others were legit crazy. 90% of the people in there, where schizophrenic, the others were suicidal or depressed. I didn't really talk to anyone, I just sat on the couch and waited for night to come.

As night came, everyone had to line up and take their night meds. When it was my turn, I had to take like eight pills. I asked the staff why this was, but all he said was that its to help us sleep. I didn't question it after that, I just took the pills and headed off to bed. The first night was hell, yelling all night, banging on doors, this happened till three AM. When I finally started to daze into my sleep, the staff opened my door. They asked how I was doing, and if I needed anything. I told them I was doing fine, and all I really needed was to get some sleep. After that they left my room, and I fell asleep.

When I woke up, I noticed a man standing in my room. He was dressed in the ward clothing, so I knew he had to be a patient, but I didn't know how he got in my room. He was just staring at me, it really creeped me the hell out. When he noticed I was awake, he got really close to me and whispered in my ear. What he said to me, had chills running down my spine.

"Don't take the medicine, you will go crazy, and they will come for you." I asked him who would come for me, and all he said was "the ones you can not see." That really freaked me out, so I got up and went to the great room. When I got there, I noticed there was a lot of people missing. I know for a fact, there was at least thirty people here yesterday, but today there was only fifteen. I seen the man who was in my room earlier, so I walked up to him, and asked him where they all went. "The ones you can not see took them," he told me. So at this point I was totally losing my marbles, and I told myself not to take the meds anymore.

Later on that night, we all lined up to take our meds. When it got to me, I told them I wasn't taking them. They told me that if I did not take them, there would be fatal consequences. So my only option was to cheek them. I successfully pulled this off, and went to my room. Later on that night, when I was trying to sleep, I heard all the door pop open. I got up to see what happened, when I heard the inner com. "They are coming, I am sorry to all of you. You must forgive me, if you all don't die I will."

I stood there in horror, wondering what in the hell I was going to do. When I finally got the courage to move, I went into the hallway, where I seen the man from before. He ran up to me, and told me to follow him. We ran through the facility, to a door that was propped open, and made our escape. We hitch hiked till we got to my moms house, I crawled through a window and woke my mother up. I told her what happened, and she called the cops. The police went to investigate,, when they got there, they were met with thirteen bodies. They did a full sweep, but didn't find any of the staff. When they got to the office, they found a secret door that led to a basement. When they went down there, the found ninety bodies of previous patients. All had their eyes, heart and tongue cut out.

That was the very last time I ever got admitted, and the man I escaped with now lives with me. We both are traumatized, and can't even leave the house. I have a girlfriend now, but when I tell her the story she doesn't believe me. I wonder what happened to all the staff, and what really was happening. I wonder if it was all in my head, or if it was just a dream. Anyways, I got to go get in line to take my meds.


Watch the video: The Truth Behind The All Seeing Eye - The Bearer of Good and Evil (January 2023).