Short-sightedness, known medically as myopia, is a common vision problem. If you’re short-sighted, you won’t be able to focus on distant objects, but will be able to see close objects clearly. Another name for short-sightedness is near-sightedness.
When you look at an object, light rays from the object pass into your eye through the cornea. This is the clear structure at the front of your eye. The light rays then pass through your lens and are focused onto the retina at the back of your eye. In a healthy eye, your cornea focuses the light towards your retina and your lens ‘fine tunes’ this.
If you’re short-sighted, it means you can’t focus clearly on distant objects. This may be because your cornea is too curved or your eyeball is too long (or both). This makes it more difficult for your eyes to focus light rays directly on your retimyopina – they are focused in front of your retina instead. If the light rays aren’t clearly focused on your retina, the object you’re looking at will seem blurred.Objects that are close to you won’t look blurry. This is because the point at which light is focused at this distance moves back into focus on the retina. The near object is therefore clear.
Short-sightedness is measured in numbers called dioptres. A dioptre is a measurement of the strength of a spherical lens and is used to grade the severity of short-sightedness. A minus sign is added to prescriptions to show what lens you need to correct short-sightedness. The higher the number, the more short-sighted you are.
0 to -3D is mild short-sightedness.
-3D to -6D is moderate.
-6D or more is high degree short-sightedness.
Does wearing glasses affect the size of your eyes?
Shockingly, there is ample scientific evidence that lenses fitted on young primates affects the development of their eyes.
In research at a New York University, biologists have demonstrated that wearing a minus lens actually causes the elongation of the eyeball, in other words it causes near sight to deteriorate. The same is the case with plus lenses fitted for presbyopia or far sight. This research into emmetropization, the eyes’ natural ability to develop clear vision, goes back to the early 1990s.
Of course the idea that glasses make your vision worse is resisted by the optic industry. Just as tobacco smoking is not considered harmful by the tobacco companies.
There are a number of ways to prevent short-sightedness. Some of these are listed below.
Eat a Balanced Diet
As part of your healthy diet, choose foods rich in antioxidants, like Vitamins A and C; foods like leafy, green vegetables and fish. Many foods – especially fish – contain essential omega-3 fatty acids that are important to the health of the macula, the part of the eye responsible for central vision.
An inadequate intake of antioxidants, consumption of alcohol or saturated fats may create free-radical reactions that can harm the macula – the central part of the retina. High-fat diets can also cause deposits that constrict blood flow in the arteries. The eyes are especially sensitive to this, given the small size of the blood vessels that feed them.
Smoking exposes your eyes to high levels of oxidative stress. While the connection has not been clearly identified, it is known that smoking increases your risk for a variety of health conditions affecting the eye.
Exercise improves blood circulation, which improves oxygen levels to the eyes and the removal of toxins.
Pregnancy and Vision
Some women experience changes in their eyesight when they are pregnant. Hormone levels during pregnancy can change the thickness of your cornea temporarily causing blurred vision. You may need different or additional vision correction for a few months. If you wear contact lenses, you may find that your eyes are uncomfortably dry during your pregnancy. The good news is that your eyes will return to normal shortly after your baby arrives.