Great illustration! Although i still cannot understand the far point, how do the eye know wether the ray comes from an object at infinity or from somewhere closer? I.e why can myopics still focus objects that are at a close enough range?
the eye doesn't really "know," but light coming from closer objects is less parallel than light from farther objects so it doesn't focus at exactly the same point. You can illustrate it with a ray diagram: in order to make an image of different objects located at different object distances that focuses and fits on the back of the eye (which has a fixed image distance) you have to have an adjustable focal point. The eye squeezes the lens to make it focus based on that.
in a myopic eye, the far point ranges from 25 cms to something less than infinity. But in the case of a hypermetropic eye, the far point is infinity.. but the near point however is way more than 25 cms.. so if an object is like 30 cms away, a myopic eye can see it but a hypermetropic eye can't cuz the image will appear behind the retina.
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Very informative, thank you.
Thank you very much, this helped me a lot!
Thank you so much for this sir it was very much understanding
U r a lifesaver dude your the best
Great illustration! Although i still cannot understand the far point, how do the eye know wether the ray comes from an object at infinity or from somewhere closer? I.e why can myopics still focus objects that are at a close enough range?
the eye doesn't really "know," but light coming from closer objects is less parallel than light from farther objects so it doesn't focus at exactly the same point. You can illustrate it with a ray diagram: in order to make an image of different objects located at different object distances that focuses and fits on the back of the eye (which has a fixed image distance) you have to have an adjustable focal point. The eye squeezes the lens to make it focus based on that.
Just wondering why my prescription has gone from sph+ .75 and .25, to plano on my recent prescription.
Sir please tell me what is far point in myopic and Hypemetropic eye
in a myopic eye, the far point ranges from 25 cms to something less than infinity. But in the case of a hypermetropic eye, the far point is infinity.. but the near point however is way more than 25 cms.. so if an object is like 30 cms away, a myopic eye can see it but a hypermetropic eye can't cuz the image will appear behind the retina.
@@mathewsjoby4519 Thanks mathews
Sir, where I can get these both lens and light?
this is the set I have: www.arborsci.com/products/laser-ray-box-and-lenses