Each morning you get up, put on your glasses and start the day, never for once realising how the miracle of corrective glasses work. You already know corrective eyeglasses help you see better. But have you ever wondered how?
With the ease of access to glasses online or in store, you never have to worry about the workings of the lenses that you don daily. You simply submit your prescription online or go to the store and have new glasses ready in a week, with almost no thought given to the science behind it. Nonetheless, if you are intrigued about how glasses help correct your vision, let’s get down to the basics.
To understand how corrective glasses work, you have to first be aware of how your eyes work. And eye impairment generally occurs depending on the shape and structure of your eye.
The retina (layer of cells), located at the back of your eye, does all the work. The incoming lights react with your retina and relays that information to the brain.
For someone with perfect vision, the light rays (from the object being viewed) come together and focus directly on the retina. The image entering your eyes must:
- Be shrunk
- Be curved (as the retina is curved)
- Be focused correctly
The cornea and pupil in your eyes are responsible for shrinking, curving and focusing the image onto the surface of the retina.
If any of these attributes are faulty, your vision is impaired, which may include blurry or unclear vision. Prescribed eyeglasses correct common vision problems like Nearsightedness (Myopia), Farsightedness (Hyperopia) and Astigmatism. How, you ask?
Myopia (nearsightedness)
This condition makes it harder to see distant objects clearly.
When light rays enter a myopic eye, the image is focused in front of the retina instead of on it. This makes it difficult for eyes to focus on distant objects. The corrective glasses (with a minus lens) for the same helps move the focus father back on the retina, for a clear vision.
Hyperopia (farsightedness)
This vision condition blurs the objects nearby making it harder to focus clearly on objects in its vicinity.
This happens because the light rays, emitted from viewed object, focuses the image behind the retina. Hence the difficulty in focusing on closer objects. Corrective eyeglasses (with a plus lens) help focus the image on the retina, providing the benefits of clear vision.
Astigmatism
In this condition, vision becomes blurred and may also cause headaches and other eye discomforts.
It occurs due to the irregular shape of the cornea (clear lens that covers your eyes) which bars the light from focusing directly on the retina, hence causing blurred vision at all distances. To correct astigmatism, cylindrical lens is used to focus light in a line to get rid of two focal points and provide one focal point for clear vision.
Now that you are versed with the basic workings of eye function and vision correction, wake up tomorrow and put on your glasses with a better understanding of why you’re doing the same.
