What Are Corrective Lenses and How Do They Work?

What Are Corrective Lenses and How Do They Work?

October 20, 2019

The way in which our vision works is fairly complex. Light enters our eye through the cornea, which is the transparent outer covering of the eye, and refracts it. In doing this, it passes through the eye where, in order to have clear vision, it must fall directly onto the retina. The retina is an area of cells at the very back of the eye that is sensitive to light. When the retina receives the light, it converts it into messages that are sent to the brain, via the optic nerve, to tell us what we can see. Unfortunately, if the light is refracted incorrectly, and doesn’t fall perfectly onto the retina, the message that is sent isn’t perfect resulting in our vision being blurred.
 

There are different types of refractive eye errors:

Nearsightedness (myopia): where you can see items close by clearly by those further away appear blurred. This is because the light is focused in front of the retina.
Farsightedness (hyperopia):  where items further away are clear but you can’t bring those close by into focus. This is because the light is refracted too far back in the eye.
Astigmatism: your eye is shaped more like a football than soccer ball, and this causes light to be focused in more than one place in the eye, resulting in generally blurred vision.

Presbyopia: this is an age-related decline of vision.
 

Fortunately, all four types of refractive errors can be rectified using corrective lenses.

 

What Are Corrective Lenses?

Corrective lenses are transparent panes of glass or plastic that are used to change the way in which light enters your eye so that it is refracted correctly.  It does this by helping your eyes to focus the incoming light directly onto the retina. Our optometrist will prescribe your corrective lenses based on the degree in which light rays will be bent, and this is measured in diopters. As a general rule, the greater the need for light to be refracted, the higher the prescription you will be given and the thicker the lenses you need will be.

 

  • If you are diagnosed with myopia, you will be prescribed lenses that are concave in order to increase the distance in which light will travel to focus it on the retina.

  • If you are diagnosed with hyperopia, you will be prescribed lenses that will reduce the distance in which light will travel to accurately focus it on the retina.

  • If you are diagnosed with astigmatism, cylinder lenses will be used to create multiple focus points.

  • If you are diagnosed with presbyopia, two types of prescription lenses work to correct your vision. Monovision lenses will correct your distance vision in one eye, whilst correcting your near vision in the other. Multifocal lenses are lenses that correct multiple distances by splitting each lens into two. The top half will correct distance vision, whilst the bottom half will correct your vision of nearby objects.

Glasses or Contact Lenses?

Corrective lenses can be placed into glasses or contact lenses. Glasses are still by far the most common solution for refractive eye errors, and the lenses can come in different types, ensuring that glasses are suitable for virtually every patient. Contact lenses sit on the eye rather than in front of it, and the prescription needed for contacts is very different to that needed for glasses. There are also many types of contact lenses available, making them suitable for a large number of patients.

 

If you aren’t sure whether glasses or contact lenses are the best option for you, our expert team would be happy to help. Please contact our office today to schedule a consultation.

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