Contact Lens Basics

A Science Lesson In How Contacts Correct Vision Problems


Contact lenses have become an increasingly popular alternative to glasses for correction of visual problems. With their ease of use and their ever-increasing level of comfort, it is easy to see why so many people have turned to contact lenses to help them see. In addition, most people find themselves to be more attractive looking when wearing contact lenses and prefer to wear them while engaging in sports. But, how exactly do contact lenses help improve site and what are the differences between the many types available?

The miracle of contact lenses

For those individuals with visual problems, there is a problem between the length of their eye and its refractive power. As a result, the eye experiences a refractive error. A refractive error is a problem in which the eye fails to focus light properly. As a result, the person has decreased visual acuity, or the ability to see clearly. The contact lens helps correct this problem by focusing the light properly onto the retina. As a result, contact lenses are capable of correcting the vision of those with myopia (near sightedness), hypermetropia (far sightedness), presbyopia, and astigmatism.

Contact lenses, which are held in place by the natural tears created by the eye, form a thin layer over the eye to assist with refocusing. For those who have myopia, the problem is with seeing objects at a distance. The contact lenses prescribed to patients with myopia, therefore, are concave. This helps to properly refocus the light onto the retina. A patient with hyperopia, on the other hand, has difficulty seeing objects close up. Therefore, convex contact lenses are used to help redirect the light in their eyes.

For those with astigmatism, the problem is a little different. An irregularly shaped cornea characterizes astigmatism. Therefore, the light entering the eye is focused on two separate points within the eye. Originally, contact lenses were unable to assist those with astigmatism at achieving better vision. New “toric” lenses, however, have been developed to help improve the vision of those with astigmatism, as well.

Presbyopia, which is the natural aging of the eye and resulting loss of sight, makes it difficult for the patient to shift from viewing far objects and near objects. This condition also makes it difficult for patients to read. Amazingly, bifocal contact lenses are now available for those with presbyopia, making it possible for them to be free from wearing glasses, as well.

Choosing the contact lenses that are right for you
With so many advancements in contact lens technology, it can be easy for a person to become confused by the multitude of choices available. Two forms of contact lenses currently available are daily wear contact lenses and extended wear contact lenses.

It is important to remove the contact lenses from your eyes before going to bed. But, with the coming of age of extended wear contact lenses, it has now become possible to wear these lenses for six nights in a row. Again another revolution, there are these continuous wear contact lenses that can be worn non-stop up to thirty nights in a row. Thecnology has made it possible as these lenses are highly oxygen permeable which helps to keep the eye healthy and irritation free.