Astigmatism is a vision condition that causes blurred vision due to the irregular shape of the cornea, the clear front cover of the eye, or sometimes the curvature of the lens inside the eye. An irregular shaped cornea or lens prevents light from focusing properly on the retina, the light sensitive surface at the back of the eye. Astigmatism frequently occurs with other vision conditions like nearsightedness (myopia) and farsightedness (hyperopia).
The specific cause of astigmatism is unknown. Astigmatism occurs due to the irregular shape of the cornea or the lens inside the eye. The cornea and lens are primarily responsible for properly focusing light entering your eyes allowing you to see things clearly. Astigmatism can be diagnosed through a comprehensive eye examination. Testing for astigmatism measures how the eyes focus light and determines the power of any optical lenses needed to compensate for reduced vision.
Persons with astigmatism have several options available to regain clear vision. The prevalence of astigmatism increases and the axis turns to against-the-rule with age. The result of the linear regression analysis indicates that the age-related change in astigmatism is mainly associated with changes in the cornea. According to the analysis of polar values by age, the regression coefficient (+/-SE) for total and corneal astigmatism was -0.024 +/- 0.002 and -0.028 +/- 0.002 , respectively.