About Your Eyes & Vision
Your eyes are a living, complex optical system. In order to have good vision it is necessary to have to healthy structures in and around the eye as well as the proper “optical” functioning of each structure.
There are a number of common “optical” or “focusing” problems that can blur your vision. These include refractive problems such as myopia or nearsightedness, hyperopia or farsightedness and astigmatism.
Myopia or Nearsightedness
Myopia, more commonly referred to as nearsightedness, is the most common refractive condition and affects one in four people in North America. Myopia allows people to see near objects clearly, but causes distant objects to be blurry. Myopia occurs when light rays entering the eye are focused in front of the Retina instead of directly on it. Myopia is usually a result of the curvature or power of the Cornea being too strong or the length of the eyeball being too long.
Hyperopia or Farsightedness
Hyperopia, or farsightedness, occurs when people see far away objects more clearly than those that are up close. Hyperopia is caused when light rays are not focused by the time they reach the Retina, rather these light rays come to a focus beyond the Retina. Hyperopia is usually a result of the curvature or power of the cornea being too weak or the length of the eyeball being too short.
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Astigmatism
Astigmatism is the result of having a corneal surface that is not regular in shape. The eye is unable to focus clearly at any distance because of this irregular focusing surface. Individuals with no astigmatism have corneas that are shaped like basketballs while individuals with astigmatism have corneas that are shaped more like footballs. There are a number of possible types of astigmatic corneas, which is why your eyes must be examined in order to determine the degree and type of astigmatism. People with astigmatism may also be myopic or hyperopic.
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Keep in mind that seeing “normally” and having clear vision requires not only that light “focus” properly, but that light be able to efficiently pass through the optical structures of your eyes. The two primary structures that are responsible for refracting, or bending light so that it can focus properly on the back of the eye, or the Retina are the Cornea, which is the outermost clear curved “lens” that is visible when looking at your eye from a side view and the Crystalline Lens, which is located behind the colored part of the eye, or the Iris, and is not directly visible. The Crystalline Lens will be examined during your eye examination by using specialized instruments to look through the Pupil, or the dark center of the Iris. Both the Cornea and the Crystalline Lens need to be perfectly clear in order for you to have good vision. If you are in good health and have not had chronic eye infections, inflammation or had any trauma to your eyes, the Cornea is likely to maintain its clarity throughout your life. The Crystalline Lens however undergoes a number of changes that progress as we age. These aging changes can affect your vision.
Usually by about the time we reach the age of 40 years old, most of us begin to experience some of the visual effects that result from changes in the Crystalline Lens. Even if you have had “good eyes” and “normal vision” all your life, your vision is likely to begin to change in a number of ways. As we progress from our 40’s, to our 50’s and then our 60’s and beyond, the most obvious changes to our vision occur as a result of these changes in the Crystalline Lens.
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The two most common changes that occur in the Crystalline Lens are:
- A loss of flexibility, called Presbyopia, which makes it harder to read and
- A loss of optical clarity, which is caused by a Cataract.
Coastal Eye Care provides medical, laser and surgical eye care for patients and is conveniently located for Eastern and Downeast Maine eye care patients.
To schedule an appointment for an eye examination, please call Coastal Eye Care in Maine at 207.667.6300.
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