Myopia and astigmatism are conditions that affect eyesight. Astigmatism develops when the cornea has an irregular shape, leading to blurred vision. Myopia develops when the eyeball is too long, or the cornea has too much curvature.
The two conditions of myopia and astigmatism often occur together. Astigmatism can also occur with another vision condition, hyperopia, or farsightedness. Although myopia and hyperopia are common alongside astigmatism, they are not directly connected to each other, and it is possible to have one without the other.
The irregular shape of the cornea in individuals with astigmatism prevents light from focusing properly on the retina, which leads to blurry vision. Astigmatism is a common condition, and most people have some degree of irregularity in the shape of their cornea. Individuals with a mild case of astigmatism will not require corrective lenses. Severe cases of astigmatism require correction to prevent blurry, distorted vision, eye pain, and headaches.
It is believed that astigmatism is a genetic condition. Children may be born with astigmatism, which either worsens or improves as they age. Corrections for astigmatism include eyeglasses, contact lenses, and refractive correction, such as laser surgery.
Nearsightedness is the more common name for myopia. It is a vision problem that makes it difficult to see things far away, while allowing the individual to see things up close clearly. The condition is caused by visual stress, such as a great deal of close work, or genetics.
Myopia most often develops in school-age children. It gradually worsens through the teen years, and tends to level off at the age of 20, when the eye stops growing. Health conditions, such as diabetes, can also lead to myopia.
The treatments for myopia and astigmatism are similar, with contact lenses, eyeglasses, and laser surgery being the possible treatment options. One additional treatment for myopia is vision therapy. Vision therapy is an effective treatment for individuals who develop myopia as a result of visual stress.
Not all cases of myopia and astigmatism are straightforward. Individuals with diabetes may experience changes in their vision depending on their blood sugar levels. When blood sugar is high, vision becomes myopic, while low blood sugar leads to hyperopia. In some cases, antibiotics can trigger myopia. Some cases of myopia do not level off with age, but continue to progress, eventually leading to blindness.
A complication of astigmatism is the condition known as amblyopia, or lazy eye. Amblyopia is a condition that develops when an otherwise healthy eye stops developing, leading to vision loss. Early treatment is necessary to correct amblyopia.