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Old 09-19-2007, 10:27 AM
Nassar Nassar is offline
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Default what is the difference between hyperopia and presbyopia?

what is the difference between hyperopia and presbyopia?


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Old 09-19-2007, 10:27 AM
Melissa P Melissa P is offline
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Hyperopia is a condition that involves the shape of the eye. The eye is too short, therefore the image focuses behind the retina, making it appear blurry.

Presbyopia, literally translated, means 'old sight'. It involved the flexibility of the lens and it's ability to accommodate. The lens becomes less flexible.
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Old 09-19-2007, 10:31 AM
yagman yagman is offline
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This is a confusing question for anyone who has not had formal instruction in the eye sciences. I would like to add my two cents and see if it helps.

Hyperopia, as has been said, is a refractive error of the eye where light from a distant object focuses posterior to the retina. A person with emmetropia (needs no glasses to correct for distance vision) can open the eyes and with no effort whatsoever see clearly at a distance and must only exert focusing effort when viewing a near object such as for reading a book. Those with hyperopia must exert focusing effort in order to see clearly at distance AND even more so at near. But as long as you are young enough to have this focusing capability you very well may not even need glasses for small or even moderate amounts of hyperopia simply because the eye is able to "focus out" the amount of hyperopia that is present. It's kind of like using one of the old 35mm cameras where you have to twist the lens to focus the camera. The brain just sends a signal to the eye to focus and BINGO things get clear for the person with hyperopia.

Presbyopia is the age related loss in the ability to adjust the focus of the eye. So, as a person who is hyperopic begins to lose their ability to focus the eye as they begin to near the age of 40, they begin to first have trouble seeing at near (remember those with hyperopia have to exert more focusing effort at near than far). As the hyperopic person continues to age and therefore lose progressively more focusing ability even distance vision can begin to be blurry because a hyperopic person even has to focus their eyes a little for seeing at a distance.

A person who is not hyperopic at all will also begin to have blurred vision at near due to presbyopia as they age. They will just notice the near vision blurring later in life than a person who is hyperopic.

I don't know if this cleared anything up or just made it more muddy. But, hope this helped.
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