Astigmatism is a visual impairment caused by a defect in the lens or corneal curvature that results in a distorted or blurred vision. Astigmatism generally appears at birth, but can also be caused by injuries suffered by the eye in the future or as a complication of eye surgery. Diseases that cause diminished visual acuity in these range of distances can be experienced also by someone suffering from myopia (shortsightedness) and farsightedness ( hypermetropy ). If left unchecked, astigmatism can cause headaches and tired eyes, especially when after using the eyes for a long time.
Causes of Astigmatism
Astigmatism is caused by a lens or cornea that does not smooth cause light into the eye, become unfocused when forwarded to the retina. Therefore, the resulting view becomes opaque.
Based on where the damage, astigmatism can be divided into 2 types. Astigmatism caused by a defect in the cornea of the eye is called corneal astigmatism, while caused by a defect in the lens of the eye is called lenticular astigmatism.
While based on the type of damage, there are two types of astigmatism, namely regular and irregular . Regular astigmatism is when one side of the cornea is more curved than the other. This condition is the most common condition and can be treated with the help of glasses or eyepiece. Irregular astigmatism is when the cornea of the eye is uneven not only on one side, but on the entire surface of the cornea. This condition is generally triggered by an injury that leaves a wound to the cornea. This condition can be treated by using contact lens, but not with glasses.
The case of astigmatism generally arises from birth, although the exact cause of why this condition appears is still unknown. There is an assumption that astigmatism is hereditary in the family. This condition is also more common in infants of low birth weight or premature birth.
Some of the causes that can cause astigmatism:
- Complications due to eye surgery.
- Injury to the cornea due to infection.
- Conditions on the eyelids that interfere with the structure of the cornea. For example there is a lump on the eyelid that suppress the cornea.
- Keratoconus and keratoglobus, conditions in which the cornea may change shape, either bulging or thinning.
- Other eye conditions that affect the cornea or lens.
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Symptoms of Astigmatism
Astigmatism causes vision impairment that can impact the patient's daily activities. Some symptoms of this condition, namely:
- A vague or unfocused view
- Sensitive to light beam (photophobia)
- Difficulty distinguishing colors that are located adjacent
- Difficulty viewing the image intact, for example a straight line that looks oblique
Diagnosis of Astigmatism
Astigmatism can generally be detected after going through a routine eye exam. Given astigmatism can arise at birth, regular eye exams are also important especially in newborns and children. Plus, children may not realize that there is a disruption to their vision power.
Several possible checks are performed to confirm the symptoms and confirm the diagnosis of astigmatism, including keratometer tests and visual acuity tests. Visual acuity test is done to test the visual acuity of an object from a certain distance by reading a board of letters known as the Snellen chart . Keratometer test performed to determine the condition of the defect in the cornea by looking at how the focus of light is forwarded by the cornea to the retina.
Other tests can also be done to measure the focus of light on the eyes. The doctor will put several different types of lenses alternately in sight with the help of a tool called phoropter. A device called a retinoscope may also be used to highlight light into the patient's eyes. That way, the examiner can assess the degree of patient's visual acuity, including the ability to focus the eyes of light.
Healthy adults over the age of 40 years and someone who has a risk of eye disease, such as diabetics, also should perform regular eye examinations. Consult with your doctor about the time of eye examination that should be done by infants, children, and adults.
Treatment of Astigmatism
In most cases, the astigmatism suffered is so mild that it does not require treatment at all. Treatment of astigmatism aims to improve the quality of vision of patients with the use of glasses, eyepieces, or through eye surgery procedures that use laser light. Treatment of astigmatism is given by its type, regular or irregular .
The use of corrective lenses can help focus the light on the corneas of astigmatism sufferers who have curved or uneven surfaces. Thus, the light entering the eye can fall right in the retina. Patients can use corrective lenses in the form of glasses or eyepieces in accordance with eye comfort and recommendations provided by ophthalmologists.
Treatment of astigmatism using laser beam aims to repair tissue in the cornea of the eye that is not as curved as it should be. The outer cell tissue present on the surface of the cornea will be removed first before the laser beam is used to alter the shape of the cornea and restore the ability of the eye to focus light. This procedure generally takes at least half an hour. Furthermore, the cornea is maintained to be restored. Several types of surgical procedures that use laser aids for the treatment of astigmatism, namely LASIK ( laser-assisted in situ keratomileusis ), LASEK (subat epithelial keratomileusis laser ), and photorefraktif keraktektomi (PRK).
Consult the type of astigmatism treatment that exists with your doctor before determining a treatment that suits the type of astigmatism you have. Learn also the pros and cons of each handling procedure available.
Complications of Astigmatism
Astigmatism experienced by one eye from birth can cause "lazy eye" ( lazy eye) or so-called amblyopia. This happens because the brain is used to ignore the signals sent by the eye. Amblyopia can be treated if it is diagnosed and treated early on before the vision path in the brain develops completely. Thus the child will be protected from lazy eye conditions.