Why Solar Eclipse sometimes causes injury to Eye

It could be injurious to eye to look at the sun particularly several minutes before and after the full eclipse. At this time our pupil become larger in size because light intensity become slows down. Our eye reacts like an automatic camera . It opens in darker and closes in brighter light. In extreme light (looking at full sun) size of pupil can be 0.1 mm in diameter and in darkest light it can as large as 9 mm in diameter. During a solar eclipse size of pupil becomes 3 or 4 mm in diameter or like due to covering most part of the sun by the moon. But the light from exposed part of the sun will not loss its power of illumination and will enter our eye affecting the macula with a greater intensity of 30 to 40 times (0.1X30 or 40) than other time of normal days and it is sufficient to burn our macula causing blindness. It can be compared with looking at torch light at night or viewing television in dark room which eventually disturb our vision but not at day time. We should remember that in any time intensity of the sun never goes down or increases or there is no variation of UV light coming to the earth from the sun. Looking at sun in normal days for longer time may also causes burning our macula of eye.
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