Colour night vision

A deficiency of this fat-soluble vitamin may result in total blindness. Found in spinach, carrots, sweet potatoes, and cantaloupe, it is responsible for maintaining good colour vision and night vision. 

Contact lenses come in a wide variety there are soft lenses and hard lenses there are some you can wear night and day for a month or more, and disposable ones that you need wear only for a day there are lenses that let your eyes breathe there are bifocal lenses and there are even lenses to correct astigmatism, a condition of the lens of the eye which makes everything seem blurred. All are products of years of research by chemical companies like Novartis, Ciba Vision, and Wesley Jessen. There are even coloured lenses that can make blue eyes bluer, and sport lenses that enable tennis players to keep their eye on the ball by enhancing the colour of a yellow tennis ball relative to its surroundings. 

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