Much like myopia (or nearsightedness), hyperopia isn't a word you hear very often. If you've heard the term if was likely in your optometrists' office and you probably have it. Your doctor of optometry might have taken the easier route though and called it by it's common, though misleading, name 'farsightedness'.
I don't know about you but when I see the word farsighted it implies that you can see far away but not up close. That simply isn't true. A farsighted person may see clearly at all distances, may have trouble at near or may have trouble seeing at all distances! To understand why we need to understand what hyperopia really is.
Hyperopia occurs when the eye is 'too weak' and light focuses behind the retina. This generally is because either the cornea (the front of the eye) is too flat OR the eye is too short (it may be a combination of both). We are all born somewhat farsighted and as we age our eyes get bigger and the farsightedness decreases. In some people the farsightedness never fully goes away. Depending on how much farsightedness there is it can cause problems like amblyopia, only cause headaches and strain while reading or even go completely unnoticed for many years. How is this possible!?
Being able to see clearly without glasses while being farsighted is all thanks to the lens inside of the eye. Its job is to flex and change shape so we can see all distances clearly without needing reading glasses. One way of thinking is that when we are reading our eyes, without the lens, would be 'too weak'. The lens changing shape gives us more focusing power so we can see. People with hyperopia have eyes that are 'too weak' at all distances, not just looking up close. The natural lens in the eye compensates for the eye being too weak both far away and up close. If they have a mild amount of farsightedness this usually doesn't cause problems but as the prescription goes up the eye and lens have a harder and harder time compensating for the uncorrected hyperopia! This can lead headaches, eyestrain or blurred vision which in children can cause amblyopia.
Light focuses behind the retina in hyperopia
One of the very frustrating things about hyperopia is that in many people it doesn't become an issue until they are in their 40's. Hyperopia is different from presbyopia (the need for reading glasses) but the same thing that causes us to need reading glasses also causes distance vision to become blurrier in farsighted people. Remember how I mentioned that the lens in the eye compensates for the eye being too weak? Eventually, in all of us, that lens doesn't work as well as it once did. That will usually start with trouble reading but in farsighted people they also eventually have blurred distance vision as well. Going from never needing glasses to needing them to see at all distances is immensely frustrating to my farsighted patients and is sometimes difficult to adapt to.
So how do we deal with farsightedness? Glasses and contact lenses are the most common and easiest forms of treatment. Both glasses and contacts refocus the light coming into the eye allowing it to focus on the back of the eye clearly. You can also consider surgery, like LASIK or PRK though they don't work as well for hyperopia as they do myopia. I'll talk about surgical options more in another blog.
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