A person suffering from hyperopia (farsightedness) often asks what causes this condition. It is often observed that people are unaware of the causes that lead to it.
There are three possible causes for farsightedness (hyperopia). These are flat corneas, genetics, and short eyeballs. A person will suffer from farsightedness will have one or a combination of these causes. I will be going in-depth with each of those causes below.
A flat cornea is a major cause of hyperopia. According to the National center of biotechnology information (NCBI), the flat cornea or in other words “cornea plana” is an unusually flat shape that the cornea develops, and the usual cornea prominence from the sclera is absent. The reduction in curvature of the cornea is the reason that leads to hyperopia in this situation. There could be other problems associated with “cornea plana” that can be developed at an early age such as “hazy corneal limbus and arcus lipoids”.
From the picture above you can clearly see how a flat cornea contributes to how the light is entering the eye. Therefore, the lack of curvature in the cornea makes the light land beyond the focus point in the retina which results in the blurry vision of the things that are near the eyes.
Have you ever had a friend whose whole family, or at least the majority, wore glasses? That is because it is common for a parent to pass on an inborn visual abnormality to their offspring (or we can use the word children, LOL).
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4136757/ states that hyperopia has 75% hereditability, only second to myopia (nearsightedness) that has an astounding 98% hereditability. The shape of the eyeball is highly dependent on our parents.
On the next point, you’ll realize the importance of our eyeball’s shape to our vision.
Although, different genetic variations have small effects on the likelihood of a person developing farsightedness. A little number of genes have been found to be associated with this condition; with that being said, none of them have a major play in the development of hyperopia. Furthermore, those identified genes have been linked with the shape of the eyeball as in its length.
For most people with farsightedness, genetics isn’t the reason behind its occurrence, but it can be a part of other problems that were caused by genetics. In other words, genetics plays a part in causing it but it is an indirect factor.
When the eyeballs are short, it causes the light that is entering the eye to land on an incorrect location. In normal eyeballs, when the light enters the eyes, the focal point registers exactly on the retina, which results in clarity in vision.
When it comes to people who suffer from farsightedness, the light that enters the eye focuses past the retina, not exactly on it. Which causes farsighted people to have a blurry vision to the things that are near them but see the objects that are farther quite clearly.
From this picture, you can see how the light enters the eyes and how it lies in the incorrect location because of the short eyeballs, or the flat cornea.
In conclusion, farsightedness is a condition that can be quite common among people and the main factors that cause it are flat cornea, genetics, and short eyeballs. While the most common causes of it are flattened cornea and/or short eyeballs, but genetic play an indirect part in causing it.