Have you ever heard of a refractive error? Refractive errors are not eye diseases; it is a result of and imperfection of the size and shape of the eye, which results in blurry or double vision. Here are some of the most common refractive errors:
Astigmatism
Many people have never heard of astigmatism, although it is an extremely common eye condition.
If left untreated, astigmatism may cause eyestrain, headaches, and blurry vision. If you have astigmatism you may not see objects in the distance or near without some form of distortion.
Symptoms of Astigmatism
Small amounts of astigmatism can go unnoticed, however, you may be suffering from eye fatigue, eyestrain, and headaches.
Astigmatism is a condition that usually can develops early in childhood. According to a study from The Ohio State University School of Optometry, 28% of school age children suffer from astigmatism. Parents should be aware that their children might not notice that their vision is blurry, not understanding that this is not normal. Nevertheless, astigmatism should be treated because vision problems can lead to learning problems and in extracurricular activities. Make sure to have your child’s eyes examined at an eye doctor’s office at least once a year.
Causes of Astigmatism
Astigmatism is generally caused by a cornea with an irregular shape. The cornea is the front, clear layer of the eye. With astigmatism, the cornea is not round and spherical and is instead irregular having two curves instead of one curve. Astigmatism in some cases could also be caused by the lens located inside the eye that is irregular in shape.
Eyes with astigmatism distort the light that comes into the eyes because the cornea is irregularly shaped. This causes the light rays entering the eye to create two images in the back of the eye (because of the two curves), instead of one image. This is what causes the distortion in sight.
Treatments for Astigmatism
For most people, their astigmatism is fully corrected using prescription glasses or contact lenses. If you select contact lenses to correct your vision, soft contact lenses are the most common option. If for whatever reason soft contact lenses are not an option, rigid gas permeable (RGP or GP) are also a great choice. Rigid gas permeable lenses usually give the clearest vision but the adaptation process will be significantly longer. Another option are hybrid contact lenses. These contacts have a center made from a rigid gas permeable (RGP) lens and an outer ring made of soft contact lens material. This type of lens provides both excellent clarity and comfort. LASIK could be another option to correct astigmatism. LASIK usually only corrects low levels of astigmatism and some patients with higher levels of astigmatism might not be candidates.
Myopia
Nearsightedness, otherwise known as Myopia, is one of the most common vision problems.
Myopia, has increased by 66 percent since 1970-1971 according to a National Eye Institute (NEI) study that compared rates of myopia in the USA with a survey conducted 1994-2004. The rate of myopia rose from 25 percent of participants to 41.6 percent.
Nearsighted people have difficulty reading signs and clearly seeing distant objects, but they can see up-close tasks such as reading or sewing, just fine.
Myopia Signs and Symptoms
Nearsighted people report headaches or eyestrain more often, and they squint or feel fatigued while driving or during sports. If the symptoms persist while wearing glasses or contact lenses, the corrective prescription may need adjustment.
What Causes Myopia?
Myopia occurs when the eyeball is slightly misshapen, longer than usual, from front to back. This causes light rays to focus at a point in front of the retina, rather than directly on the surface.
Nearsightedness runs in families and usually begins during childhood. This vision problem may stabilize at a certain point, although it also may worsen with age.
Myopia Treatment
Nearsightedness is mostly corrected with glasses, contact lenses or refractive surgery. Depending on the degree of myopia, you may need eyeglasses or lenses all the time, or only when sharper distance vision, like driving, or viewing a chalkboard, movie etc., is desired.
If your glasses or contact lens prescription begins with a minus number, e.g: -2.00, you are nearsighted.
Refractive surgery is a more “permanent” option for correcting myopia. This includes laser procedures such as LASIK and PRK, or non-laser options such as corneal inserts and implantable lenses. One advantage of the non-laser options is that, although they’re intended to be permanent, they may be removed in case of a problem or change of prescription.
Orthokeratology is a non-surgical procedure where special rigid gas permeable (GP) contact lenses are used to slowly reshape the cornea during sleep. After the lenses are removed the cornea retains the new shape. The patient can see clearly during the day without wearing glasses or contact lenses.
Hyperopia
Hyperopia -Farsightedness, is a common vision problem affecting about 25% of the U.S. population. Hyperopia sufferers can see distant objects well, but have difficulty seeing up close objects.
Hyperopia Symptoms
Farsighted people might have headaches or eyestrain, and find themselves squinting or fatigued doing anything which is close-range. If you still experience symptoms such as these with glasses or contact lenses, your eye prescription most likely needs to be updated.
What Causes Hyperopia?
Farsightedness is typically when the eyeball is shorter than normal so the light rays entering the eye focus behind the retina, rather than on it. Many children are born with hyperopia, and some outgrow the problem as the eyeball lengthens with normal growth.
Some confusion exists between hyperopia and presbyopia, since both conditions involve difficulty with up close vision. Presbyopia has a different cause and occurs after age 40.
Hyperopia Treatment
Eyeglasses or contact lenses almost always can correct farsightedness by changing the way light rays bend as they enter the eyes. Your glasses or contact lens prescription will begin with plus numbers, +2.50, +4, etc. when you are farsighted.
Depending on the amount of farsightedness you have, you may need to wear glasses or contact lenses all the time, or only during reading, or work.
If you work prolonged periods on a on a computer screen or do other close-up work for long periods consult with your eye doctor for special work prescription glasses.
Refractive surgery, such as LASIK or PRK, is another option for correcting hyperopia.
If you think that you show signs of one of these conditions, please call us today to schedule your appointment for an eye exam!
