What causes poor eyesight?
Poor eyesight is a very common problem caused by refraction defects in the visual field. The majority of them are caused by changes in the length, and internal structures of the eye, and their causes are summarized as follows:
Myopia
It happens when the eyeball grows larger, and light rays converge in front of the retina. In this situation, patients will have poor eyesight when trying to focus on distant objects, which is why this condition is also known as nearsightedness.
Hyperopia
It happens when the eyeball becomes smaller, and light rays converge behind the retina. In these cases, the patient will have poor eyesight when trying to focus on nearby objects, which is why this condition is also known as farsightedness.
Astigmatism
In astigmatism, the problem is not the length of the eye but the transparent structures that accommodate vision and allow light to enter in contact with the retina. In astigmatism, there’s a problem with the normal curvature of the lens or the cornea. Thus, light still passes through but in a different way. This causes a fuzzy and distorted vision that may be accompanied by myopia or hyperopia.
Presbyopia
It is an age-related change to the muscle fibers that accommodate vision. They are attached to the lens and change its structure to focus on nearby or distant images. However, in presbyopia, these structures lose their flexibility and become stiff, unable to change the shape of the lens when images are too close.
These are the most common causes of poor eyesight, but there are many others related to chronic health conditions such as diabetes or hypertension. Thus, regardless of your age and health conditions, it is important to pay attention to any signs and symptoms of eye problems. Even if visual problems appear not to be a severe problem, the microvasculature of the eyes reflects any problem we have in other parts of the body. Thus, it is very important to perform a complete eye examination as a part of your annual screening, even if you do not yet have any concerning symptoms.