The Types Of Astigmatism
Astigmatism might be one of the most misunderstood optical defects. First of all, it is a refractive error. This means it is not an eye disease nor is it an eye health problem. Instead, there is a misalignment with how the organ focuses light. For those with this optical dilemma light does not divert to a single point on the retina. Consequently, the resulting vision is blurry. Squinting is a common symptom. Unlike near or farsightedness, vision tends to be somewhat blurred at all distances. Uncorrected cases cause strain or headaches following hyper visual tasks such as reading. Typically, irregularly shaped corneas instigate the problem. Additionally, some astigmatisms are caused by irregularly shaped lenses.
The meridian of the eye is a sort of level plane traveling from one end to the other. Think of it as a focal line. Normally, these lines allow for light to focus in one spot on the retina. However, in differently shaped eyes, the light hits multiple areas of the retina. Myopic astigmatism results in nearsighted meridians in one or both of the eyes. This means the first focal line is in front of the retina and the second is behind. Compound myopic cases have both focal points before the retina, though they often settle on separate points. Treatment usually entails strong eyeglass prescriptions or protective lenses. In the more severe cases, corrective surgery may be an option.
Hyperopic astigmatism is the natural opposite to myopic cases. Like its counterpart, there are two types of manifestations: simple and compound. For hyperopic cases, either one or both focal points are situated after the retina. This results in blurry and farsighted vision. Generally, treating this variation of astigmatism requires a prescription of corrective lenses. Convex lenses are often the preferred method of treatment. Minor cases may be left untreated, as they do not significantly impact daily life. For those who wish to do away with corrective eyewear, surgical procedures may correct the problem either partially or entirely.
The third major type of astigmatism is called mixed. In these cases, one principal meridian is farsighted, while the other is near sighted. This means the focal lines concentrate on either side of, or straddle, the retina. Due to the complexity of these cases, treatment may be a bit more difficult or have less predictable results. With some individuals, a corrective lens prescription may work. LASIK surgery can result in successful correction of vision. However, the risk for incomplete correction is higher than when dealing with simple myopic or hyperopic astigmatisms.
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Jessica is an experienced eye care specialist. You can find her thoughts at visioncareguides.blogspot.com.
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