how does the solar eclipse effect our eye?? i wud like to know it in full details pls..... thanks !!!?

Question

hey guys..... thanks for the replies.... but wht i actually want is to know bout the eye in specific...... like wht happens to the retina - the rods & cones, wht chemical changes r takin place because of the rays absorbed by the eye?????

Answer 1

No one has yet given the real reason. It is because UV radiation from the sun (the frequency of light that does the most damage to your eyes) does not significantly diminish during an eclipse. So when you look at the sun when it is much more dim (like during an eclipse), your eyes are more dilated and you let in MUCH more damaging UV radiation, and because the sun appears more dim, it seems more comfortable to look at it for prolonged periods.

Through a telescope, you will cause blindness. Looking for prolonged periods with the naked eye will cause temporary color blindness, color blindness and then blindness and cataracts.

You can look at the sun through a telescope that has a special "solar filter" attached to the lens. You can also use the "camera obscura" trick - poke a small pin hole in a sheet of aluminum foil and hold it away from a sheet of paper out in the sunlight. When it's in focus, you can see sun spots and eclipses.

You can also aim the eyepiece of your telescope at a sheet of paper on the ground and it will create a really nice projection of the sun's image on the paper... just don't look through the telescope to align it with the sun!!! Some telescopes have a white viewing card that attaches to your telescope for this very purpose.

Answer 2

•Eclipse blindness results from retina burn--i.e., the retina is damaged by heat due to solar radiation passing through the lens of the eye, much as rays focused by a magnifying glass can light a fire. Some authorities feel a more likely explanation is photochemical damage. Were heat the culprit, they argue, eclipse damage would happen quickly, but evidence suggests it accumulates over repeated viewings during the several hours of the event. •You can go permanently, totally blind staring at the sun during an eclipse. Permanently, maybe. Totally, probably not. An hour of rooting around in the journals turned up no cases of permanent total blindness; even cases of severe initial impairment mostly turned out to be temporary. No guarantees, though--one London eye hospital reported that 10 percent of the eclipse victims they treated suffered some permanent vision loss. •Glancing at the unoccluded sun for a split second will ruin your eyes. Nonsense. While you may be briefly dazzled, your body's reflexes--rapid contraction of the pupils, averting your eyes--will likely kick in, limiting the danger. For normal unprotected eyes, the damage threshold is in the neighborhood of 30 seconds of direct exposure--still not a long time, I admit. -

Answer 3

Most of these replies are wrong!

A totally eclipsed Sun is no danger at all: the bright photosphere is completely blocked by the Moon, and the light coming from the Sun's corona is dim and harmless (and extremely beautiful!)

The danger comes just before and just after totality, when only a thin sliver of the photosphere is visible. Because it's a thin sliver, our normal reflexes to look away are inoperative, and so the full radiation from the photosphere falls on our eye's retina. The damage is _not_ from UV (ultraviolet) light, as someone said, but rather from the other end of the spectrum: infrared (= heat). What happens is that the heat from the Sun concentrated on our retina actually COOKS the cells there (yuck!)

What happens on a properly conducted eclipse expedition is that special dense filters are used to view the partial phases of the eclipse. Then, at the moment totality begins (Sun fully covered by Moon) someone yells "Filters off!" and everyone removes their filters and looks directly at the eclipsed Sun, one of the most beautiful sights in all of nature. At the end of totality, the Sun breaks through the valleys at the edge of the Moon (called Bailly's Beads), and everyone puts their filters back on to view the final phases of the eclipse safely. I've been on two eclipse expeditions, in 1963 and 2006, and this procedure was followed each time and everyone viewed all phases of the eclipse in perfect safety.

Answer 4

Looking directly at the photosphere of the Sun (the bright disk of the Sun itself), even for just a few seconds, can cause permanent damage to the retina of the eye, because of the intense visible and invisible radiation that the photosphere emits. This damage can result in permanent impairment of vision, up to and including blindness. The retina has no sensitivity to pain, and the effects of retinal damage may not appear for hours, so there is no warning that injury is occurring.[31]

Under normal conditions, the Sun is so bright that it is difficult to stare at it directly, so there is no tendency to look at it in a way that might damage the eye. However, during an eclipse, with so much of the Sun covered, it is easier and more tempting to stare at it. Unfortunately, looking at the Sun during an eclipse is just as dangerous as looking at it outside an eclipse, except during the brief period of totality, when the Sun's disk is completely covered (totality occurs only during a total eclipse and only very briefly; it does not occur during a partial or annular eclipse). Viewing the Sun's disk through any kind of optical aid (binoculars, a telescope, or even an optical camera viewfinder) is even more hazardous.[32]

Glancing at the Sun with all or most of its disk visible is unlikely to result in permanent harm, as the pupil will close down and reduce the brightness of the whole scene. If the eclipse is near total, the low average amount of light causes the pupil to open. Unfortunately the remaining parts of the Sun are still just as bright, so they are now brighter on the retina than when looking at a full Sun. As the eye has a small fovea, for detailed viewing, the tendency will be to track the image on to this best part of the retina, causing damage.

Answer 5

Aviophage is right.

The eclipse itself is not the danger. It is simply dangerous to look directly at the Sun for more than a few seconds. Normally, if you look at the Sun, you have the reflex of turning away.

However, when you know that there is something going on, you may be tempted to keep on looking, in the hope of seeing the eclipse. That is the danger.

It gets even more dangerous when people use devices to make the sun appear brighter (like binoculars or telescopes).

The rays from the sun are not MORE dangerous during an eclipse. However, they are not LESS dangerous either. The rays from the sun are LWAYS dangerous for the eyes if you look at the sun without proper protection.

Sunglasses (even those against UV rays) are NOT proper protection. Smoked glass is not OK. Using exposed Black & White (or color) film negatives is NOT good protection.
Some grades of welder's glass (e.g., number 13) may be good. Mylar solar filters specially designed for astronomy are also OK.

Answer 6

It is exactly the same as when the Sun is not eclipsed. The only difference is that a 99% eclipsed sun can be looked at without feeling pain, but it still have enough brightness to damage your eye. It basically burns the cells in your retina where the lens focuses the light.

Answer 7

You're eye uses a lens to focus an image on the retina, where the sensory cells "see" the image and transmit the signals of the image to your brain.

If you've ever used a magnifying glass to focus the sun to burn wood, paper, or bugs, well, that's what the lens in your eye is doing to your retina.... It isn't a good idea. Even when the sun is partially hidden by the moon, there is still enough light to damage your eyes, so... be careful. The best way to view an ecclipse is one that we crafted in Cub Scouts - get a large board, and drill about 1/4" or 3/8" hole, and hold it about 3 feet off the ground. The image of the sun will appear in the shadow of the board. (It's called the pin-hole camera effect.) Much safer, and you get to see the ecclipse.

Answer 8

It isn't the eclipse itself that can damage your eyes, but looking at the sun. Normally the sun is so bright that your eye will not permit you to look directly at the sun. During an eclipse, though, the sun's light may be dim enough that you can look at it, but still bright enough to injure your eye.

Never look toward the sun except through a solar telescope or a welding mask or welding filter.

Answer 9

X-ray, radiowaves, ultraviolet rays are always there. Most of the time it hurts to look. Have you ever had welders flash? It sucks, it is a sunburn on your eyes and it hurts to blink.

Answer 10

Same as the regular Sun. The Astronomer told his student that he had been studying the sun all day. When the student asked him what he learned, he said, "not to study the sun all day."