Characterizing astigmatism in the United States

Area of Science:

• Ophthalmology
• Public Health
• Epidemiology

Background:

• Astigmatism is a common refractive error affecting visual acuity.
• Understanding trends and demographic associations of astigmatism is crucial for eye care planning.

Purpose of the Study:

• To determine changes in the prevalence of astigmatism in the U.S. from the 1970s to the 2000s.
• To identify demographic factors associated with astigmatism and its rule.

Main Methods:

• Retrospective cross-sectional study using National Health and Nutrition Examination Survey (NHANES) data from 1971-1975 and 1999-2008.
• Astigmatism was measured using algorithms based on visual acuity, lensometry, and objective refraction.
• Logistic regression models assessed demographic associations with clinically significant astigmatism (≥1.0 D) and against-the-rule (ATR) astigmatism.

Main Results:

• Astigmatism prevalence increased from 14% in the 1970s to 24% in the 2000s.
• This increase was more pronounced in men than women.
• In the 2000s, myopia was associated with 8.34 times greater odds of astigmatism. ATR astigmatism was more prevalent in men, nonmyopic individuals, and older adults (60-74 years).

Conclusions:

• The prevalence of astigmatism and ATR astigmatism has increased significantly in the U.S. over three decades.
• Being male, White, and nonmyopic are factors associated with ATR astigmatism.