In America alone, there are more than 35 millions of people who choose to wear contact lenses because they are much more convenient and practical than wearing glasses.

People choose to wear contact lenses for different reasons but one thing is certain, lenses are much preferred for a fact that they don't alter your appearance the way glasses do.

For those who need vision correction, contact lenses offer an easy and invisible solution yet NOT everyone wears them for corrective purpose.

Nowadays, contact lenses are often used to enhance one's appearance and style by way of changing the color of the eyes. You'll be surprised how easy it is to switch to a different eye color by wearing transparent or opaque colored contact lenses.

But it is only in the case of vision correction, a question might pop in your mind about "how do contact lenses work?" With that in mind, let's talk a look at how they correct refractive vision problems.

Contact lenses are thin transparent plastic discs that sit on the cornea. Lenses stays in place owing to the pressure exerted from the eyelids as well the layer of tear fluid produced by your eyes naturally.

As the eye blinks, it provides lubrication to the lens and helps cleanse away any impurities that may have settled upon the lens.

The basic principle of how do contact lenses work is the same. They are used to correct refractive vision problems in much the same way eyeglasses are. This could be anything from presbyopia to farsightedness to nearsightedness, etc.

With these conditions, the eye doesn't focus light directly on the retina as it should, leading to blurry vision. Thus lenses (or glasses) are used to help the eye refocus the light directly onto the retina.

There are different types of contact lenses for each of the different types of vision problems.

These lenses are shaped in the way that the curvature of the lens takes the light to whichever direction it needs to go in.

For Myopia

To correct nearsightedness, the contact lens is thinner at the center than at the edges. It bends light so that it converges further back in the eye, reaching the retina and correcting nearsightedness. These lenses are called "minus", or concave lenses. You can see that in your prescription with numbers like "-2.75" or "-3.25."

For Hyperopia

If you suffer from farsightedness on the other hand, the contact lenses would be just the opposite in order to correct the vision. The lens is thicker at the center and thinner at the edges. It bends light to converge further forward in the eye, landing on the retina and correcting farsightedness. These lenses are called convex lenses or "plus".

For Astigmatism or Presbyopia

In the case of astigmatism or presbyopia, the eye loses its ability to shift focus between far and near objects, distorting vision. To correct astigmatism, the lens is designed specifically to the individual's correction needs.

While lenses used to correct myopia and hyperopia are spherical, astigmatism requires a special lens, called a toric lens. There are also "bifocal" contact lenses for those with presbyopia. These lenses have two prescription in the same lens to meet dual vision needs.

In short, the answer to how do contact lenses work is based on what imperfection your vision is but the principle remains the same, i.e. the lenses are shaped in such a way that it would facilitate the light to bend correctly on the retina for crystal clear vision.