So how much total power does the eye roughly have as a refractive device and how much of that is contributed by the corena ,so how much is delivered by the lens?
So how much total power does the eye roughly have as a refractive device and how much of that is contributed by the corena ,so how much is delivered by the lens?
This is from memory only: Average: 64 diopters. About 17 from lens, most of the rest from the cornea. But lenses can have much more or less. Cornea's can have from less than 39 to over 80 (keratoconnus). Any basic anatomy book or most books on eyes, or optometry or contact lenses, or spectacles will tell you at least as much as my old memory.
an emmetropic eyeball has 59-60 diopters. The lense and cornea combined should match the focusing power of the eye. The lense has about 15 diopters and the cornea 45 diopters. My cornea has 44 diopters and my lense probably 15. I could see fine till I was 12 when I became myopic. I experienced an increase in axil length over the years till my eyeball went from 24mm to 26mm and my sphere is now -5 because I need this amount of subtraction to compenstate for my enlongated eyeballs having too much focusing power, images focus in front of my retina, resulting in a 20/500 blur!
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