What materials are used in lenses ?
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The lens elements are made of transparent materials. Glass is the most widely used material due to its good optical properties and resistance to scratching. Various plastics, such as acrylic (or PMMA), the material of Plexiglas, can also be used. Plastics allow the manufacture of strongly aspherical lens elements which are difficult or impossible to manufacture in glass, and which simplify or improve lens manufacture and performance. Plastics are not used for the outermost elements of all but the cheapest lenses as they scratch easily. Moulded plastic lenses have been used for the cheapest disposable cameras for many years, and have acquired a bad reputation: manufacturers of quality optics tend to use euphemisms such as "optical resin".
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a double convex lens will magnify, i can't remember which ones reduce size, but i'm guessing some sort of concave lens, and lenses REFRACT light, while mirrors REFLECT light.
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Most goggles are made of plastic. The straps and eye cup gaskets are made up of rubber, latex, and/or silicone.
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Tinted contacts help to create more contrast and eliminate shadows, thus making images more crisp. I think the lenses are tinted amber (yellowish-orange) for outdoor sports.
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I prefer contact lenses because they reduce glare.  Glasses tend to get heavy after a while.  Although, glasses are fun to put on top of your head to hold the hair back out of your face.
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The speed of light is the ratio of electric permitivity to magnetic susceptibility. So prisms, lenses, Pockel cells. Maybe those magnetic seals. An ion filter that blocks electric DC fields, but not alternating.
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for the size of the lens i would go back to the lens maker formula it is:\npower of lens = (n(lens) - n(0)) * (1/R1 - 1/R2)\nwhere n(lens) is refractive index of lens material\nn(0) is refractive index of the medium in which lens is kept\nR1 and R2 are surface radius of the two sides of the lens.\nso you can see from the equation to increase power of the lens we can either increase refractive index of the lens (assuming we are seeing it in air) or reduce the radius of curvature of the lens sides. so ideally as power increses the radius of the lens decreases and so the size of the lens also reduces. you can also check out gullstrands equation for further reference of thicker lenses. hope this helps
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learn more about different plastic materials
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Use fingernail polish remover. That's the standard method.\n\nHowever, test in a corner of your lens first. If your lenses are made of some variety of plastic, the fingernail polish remover might affect the plastic too.
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This is something you learn best through hands-on... but here's a couple of sites to help you. For most simple equipment like magnifying glasses or balance scales, use the package insert for details.\n\nhttp://www.ekcsk12.org/science/lelab/microscopeuselab.htm\n\nhttp://www.mdk12.org/instruction/curriculum/science/safety/safety.html
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Polarized lenses have tiny, tiny, stripes of opaque material built into them. We're talking microscopic here. Light that hits the lenses is only allowed through in one orientation, reducing its intensity by 1/2 on average.\n\nPicture a a thick slicve of cheese, hurtling towards a cheese grater at hundreds of miles and hour. The cheese grater consists of narrow slits spaced with sharp blades which point towards the incident cheese. When the cheese goes through, it will be sliced into a thinner slice that is aligned with the slits. That's sort of what happens to the light.
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Simple Green! Walmart or any grocery store carries it. Clear bottle dark green liquid. Spray it on half strength and let them sit for a few minutes...then spray them again. Gently rinse off and use the pads of your fingers (Index and middle finger on the outside while your thumb is rubbing on the inside) of the lens. Cloths leave microscopic scratches that ruin your glasses. Hope this helps!
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polarized lenses. they come in a variety of colors and degrees of darkness. a good way to tell if the lenses are polarized is take your digital lcd watch and look at it while wearing the glasses. when you look at it straight on it will be clear but turn the watch and the numbers will darken then disappear.
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Use of a fresnel lens, a lens made up of circular rings that focus the light to the small area of reflecting mirror. This in turn projects the image to the screen. \n\nTake the optic workings of a telescope or microscope:\n\nOptics - microscopes and telescopes all invert the image because if they didnt, it would mean that another lens had to be added, increasing money cost. A lens is convex on both sides. That means the middle is thicker than the edges. A microscope or telescope has two lenses (basically).\nThe objective lens (usually larger and closer to the specimen or object) which allows the image of the object to be reduced to a smaller workable image inside the scope. \nThis image is inverted inside the scope. It is also too small to see with the eye, so you need another lens, the eyepiece. The eyepiece focus's your eye on the image and magnifies \nit so you can see it. Every lens has a focal length, the point at which the image is formed away from the surface of the lens. \n\nOk now we take this to the overhead:\n\nSame principle but in different Direction. You manipulate the object, transparency, over the light source after the light is passed thru the fresnel. The fresnel forms the smaller inverted image on the mirror. It is then reflected to the screen where the focal length is adjusted (moved closer or farther away from the screen )
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The refractive index of a material depends on how it responds to magnetic fields (quantified by its permeability) and electric fields (quantified by its permittivity). The refracive index is given by the square root of the product of these.\n\nFor normal transparent material, both are +ve, so this square root is real. For things like metals, one or the other is -ve, and the refractive index is imaginary (ie involves the square root of -1). These materials are opaque.\n\nBut for meta materials both are -ve. So the refractive index is once again real, but because these materials have odd behaviours the normal convention of using the +ve root for the refractive index is reverse, and a -ve is used.\n\nMeta materials still slow light down, but some of the usual rules are reversed. For instance, the doppler shift is reversed and snells law works in the opposite direction.
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Something with lenses and light!
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There are many different types of lenses. Here's a site with good information.