As we discussed in the Hyperopia page on this site, many patients will tell me they always get confused with the terms farsighted and nearsighted.
Why they so hard to remember which is which?
The reason is that they have a positive connotation.
They indicate what is good about your vision. Not what's wrong.
So, you can think of Nearsightedness as a condition where objects are in greater focus for you at near ranges.
With Farsightedness, just remember that objects are in greater focus far away.
WHAT CAUSES MYOPIA?
When light rays enter the eye through the cornea, they refract/bend towards each other (converge).
Next, they go through the lens in your eye and they converge together even more.
Because the light rays are converging towards each other, they will eventually meet together at some point of focus.
If that point of focus occurs at the fovea in the back of the eye, then the object you are looking at will be clear.
Myopia is when the light rays converge a little too much and the focus point occurs before they reach the fovea (central point in the retina).
As a result, the object becomes blurry until you move closer or bring it closer to you to sharpen its focus.
What causes the light rays to converge too much so that they focus before reaching the fovea?
This is usually due to a few possible reasons.
Longer eyeball (from front to back)
More curvature in the cornea or lens (these two structures contribute to most of the eye's refracting power).
Now that you know how it works... you might be asking... why would the eyeball grow so long, or why would those structures of the eyes be shaped that way?
The reasons the eyes become that way are usually a mix between genetics and lifestyle.
With lifestyle, the theory goes that we spend less time outdoors, and more time viewing closer and closer objects (phones, devices, reading material, computers etc.) As we focus on near objects for so much of the day, and adaptation occurs and the eyes actually change because of these habits.
ETHNICITY AND NEARSIGHTEDNESS
Epidemiological research has confirmed that East Asian people have the highest rates of Myopia and that Black Africans have the lowest rates of Myopia.
Again, this does not confirm that genetic differences are the sole reason for Myopia because there are significant lifestyle factors that might also come into play.
Many people might think that corrective lenses treat nearsightedness. The problem is, they only correct the distribution of light inside the eyes... i.e. they change the way light bends before reaching the eyes.
The optical problem is "corrected", but you are still nearsighted.
For this reason, we probably ought to refer to your lenses (contacts or eye glasses) as "compensatory lenses" because they are not really "treating", "curing", or "correcting" your eye condition in any permanent way.
Many people (parents especially) are concerned about Myopia getting worse from year to year.
If you are interested in slowing down or trying to stop your nearsightedness from worsening, you now have a few options.
ATROPINE EYE DROPS
This is a medicine used "off label" which has been shown to reduce the rate of Myopia progression in kids.
This is a gas permeable contact lens worn exclusively at night which gently reshapes your cornea. When you wake up, you take your contacts out, and your vision should remain clear all day. Orthokeratology has also been found to lower the rate of Myopia progression.
MULTIFOCAL (BIFOCAL) CONTACTS
These types of contacts are classically used for those with Presbyopia but they have also been shown to reduce Myopia progression.