jfarkinB: Glasses and contacts have been a nuisance, but I've finally reached the age where myopia is adaptive. I can still hold something in my hands and take a close look at it without glasses, where most people my age need reading glasses./still hoping for that effective presbyopia treatment//MIGHT consider elective eye surgery at that point
erewhon: Or, as is obvious to the casual reader, there is a complex enzymatic control system in the eye for long term correction of focus. It regulates the length of the eyeball, and is controlled by the rods in the periphery of the retina.Bright sunlight suppresses the production of the enzyme that triggers eye lengthening. In addition, the retina periphery can detect whether the focal plane is falling in front of or behind the retina. If, over a long period of time, the peripheral focal plane falls in front of the retina, the enzyme is suppressed, shortening the eyeball to bring the entire retina in focus, not just the macula area. Constant focusing on near objects also moves the peripheral focal plane behind the retina, triggering a long term correction that induces myopia.Corrective lenses can be designed two ways - to focus tangent to the macula and in front of the periphery, or tangent to the macula and behind the periphery. They're always ground to focus behind the periphery. This triggers the long term correction system to lengthen the eyeball to bring the periphery into focus as well. This makes the eye more near-sighted. So you get a stronger corrective lens, the focus again moves behind the retina, more lengthening. Thus do you get progressive myopia.
Dion Fortune: It's sad how people think myopia is something natural, along with obesity and other health problems that are on the rise these days. And nobody does anything about it in terms of prevention. My parents generation is from a developing country, they had little education or electricity, ie didn't spend their days watching teevee and reading schoolbooks, not a single one of them has bad eyesight (well, until they got old). My siblings and I who were born in raised in America: BAM, every single one of us has terrible myopia. Humans are like the proverbial frog in the pot that doesn't realize the water is on the stove until its too late and they die.
Fano: It's the price we pay for literacy.
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