what is the difference between hyperopia and presbyopia? The eyeball of a farsighted person is shorter than normal.
Many children are born with hyperopia, and some of them "outgrow" it as the eyeball lengthens with normal growth.
Sometimes people confuse hyperopia with presbyopia, which also is a difficulty in seeing up close, but has a different cause.
When people develop presbyopia, they find they need to hold books, magazines, newspapers, menus and other reading materials at arm's length in order to focus properly. When they perform near work, such as embroidery or handwriting, they may have headaches or eyestrain, or feel fatigued.
Presbyopia is caused by an age-related process. This is different from farsightedness, which is related to the shape of the eyeball and caused by genetic factors, disease, or trauma. Presbyopia is generally believed to stem from a gradual loss of flexibility in the natural lens inside your eye. Did I confuse you more? I hope not! I hope this helps! O^O hyperopia is far sightedness presbyopia is the lessening of visual acuity with age... the opposite of hyperopia is myopia which is nearsightedness... 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. The main difference is the underlying causes:
Hyperopia is due to the eye being too short and the light focuses behind your retina. Presbyopia is due to the stiffening of the crystalline lens inside our eye that normally would flex for focusing on near objects. Hyperopia is a refractive error that typically does not change much once in adulthood. Presbyopia does not start to become noticeable until a person is around 40.... and this condition will happen to everyone!! Once the lens starts to loose its flexibility you begin to loose your ability to focus at near. This progressively gets worse until it levels off when a person is in their late 50's/early 60's. This is when all focusing ability is lost and reading glasses/bifocal/multifocal correction will be needed. This is a normal part of aging :)
Anyways hope this helps :) 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. The eye is a system to focus light on the retina where a digital signal is generated and the brain has the software to generate an image from these electric impulses. The front surface of the cornea and the lens are the main refractive surfaces (where the light rays bend). In a normal eye the rays focus and form a clear image on the retina. In hypermetropic eyes the light rays focus behind the retina and a blurred image is perceived. In presbyopic eyes the lens becomes hard and rigid and cannot become more spherical when you view near objects and the ciliary muscle in the eye relaxes, again, the light rays focus behind the retina and a blurred image is seen. That is the reason why both conditions are corrected with convex + lenses. As another myope with presbyopia I can tell you this:
In my younger years, if I looked at the back of an aspirin bottle, I'd practically have to stuff it up my nose to read.
Now, in my forties, without my glasses, I have to 'trombone' my arm.
Thanks to Varilux (the best lenses on earth) I can see all distances accurately, and not look like an old fart! | 