Astigmatism is a refractive error of the eye is also called a cylinder. This occurs because of improperly curved cornea, the light beam is not broken in all meridians equally, and sometimes because of the irregular curved lens of the eye.
Symptoms of Astigmatism
Astigmatism usually occurs in combination with kratkovidnošću or foresight. Symptoms include blurred and blurred vision, distorted images, or distorted capital letters when reading. In mild astigmatism person does not always notice the existence of disturbances, blurred vision corrected because of accommodation (adjustment of lens of the eye to watch the vicinity). While a high degree of astigmatism causes significant problems with vision, and it is impossible to neprimjetiti. When children are reading occurs in long-term headaches and increased fatigue.
Types of astigmatism
Regular (regular) Astigmatism - The case for more than 80% of people with astigmatism regular astigmatism is when the two principal meridians are designed at right angles. This astigmatism is usually subject to correction. If the principal meridians lie at right angles, but are set obliquely, this is called astigmatism, oblique astigmatism.
Regular astigmatism can be divided into:
Simple astigmatism - one meridian is hyperopic or myopic.
Compound Astigmatism - Both meridians are nearsighted or farsighted.
Mixed astigmatism - one meridian is hyperopic and one myopic.
Irregular (irregular) astigmatism - The two principal meridians are perpendicular to each other. This type of astigmatism is mainly caused due to corneal disease (keratoconus), or occurs as a result of injury or inflammation of the cornea.
Astigmatism Astigmatism is referred to as "by rule" if the vertical meridian rays of light breaking more than horizontal. When the opposite case, ie when the horizontal meridian rays of light break stronger than the vertical meridian, such as astigmatism are marked astigmatism "against the rules."
Correction of astigmatism
Regular astigmatism can be corrected dioptric glasses, toric contact lenses, or surgery. This branch of surgery is called refractive surgery. Correction of irregular astigmatism is difficult, use the contact lenses, sometimes helping only operations. Astigmatism can be stable, but also the condition often worsens because it is extremely important to regularly consult an ophthalmologist or optometrist, for obtaining the necessary corrections.