Review: Uncorrected Refractive Error

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The VEHSS team conducted a review of published literature on examination-based population studies reporting the prevalence of uncorrected refractive error.

There are four different types of refractive error (RE): myopia, hyperopia, astigmatism, and presbyopia. Myopia, also known as nearsightedness, refers to light focusing in front of the retina, causing distant objects to look blurry.(NEI, 2015) Hyperopia, also known as farsightedness, is caused if the cornea in the front of the eye is too curved and light does not focus correctly.(AOA, 2015) Closer objects are out of focus for people with hyperopia. Astigmatism refers to an irregularly curved lens.(AOA, 2015) Astigmatism often occurs with hyperopia and myopia. Presbyopia is age-related and occurs when the lens loses the flexibility to change, making it hard to focus on close objects.

Refractive error is diagnosed through visual acuity testing, refraction, or a comprehensive eye examination.(Dhaliwal, 2015) Refractive error can be treated with corrective eye glasses, contact lenses, and refractive surgery. Refractive error that is not diagnosed or treated is called uncorrected refractive error (URE). Uncorrected refractive error is often defined as presenting visual acuity (VA) of 20/50 or worse, and best corrected VA of 20/40 or better, indicating that normal acuity may be achieved through refraction correction.(Qui, 2014) Refractive error can remain uncorrected due to the limited availability of practitioners, affordability of examinations and treatments, lack of awareness by the patient or family, and cultural stigmas against glasses.(Qui, 2014)

Uncorrected Refractive Error Literature Review Results

There were 10 studies published between 2005 and 2016 that examined the prevalence of uncorrected refractive error.

Table 1. Uncorrected Refractive Error Prevalence Sources.

Uncorrected Refractive Error Prevalence Sources
Author Date of Publication Title Date of Data Collection Data Source Sample Size Prevalence Data Stratified by:
Varma R, Choudhury F, et al. 2016 Prevalence and Causes of Visual Impairment and Blindness in Chinese American Adults: The Chinese American Eye Study 2010–2013 CHES 4,582 Race
Fisher DE, Shraqer S, et al. 2015 Visual Impairment in White, Chinese, Black, and Hispanic Participants from the Multi-Ethnic Study of Atherosclerosis Cohort 2002–2004 MESA 6,134 Not stratified by demographic variables
Qiu M, Wang SY, Singh K, Lin SC. 2014 Racial Disparities In Uncorrected and Undercorrected Refractive Error in the United States 2005–2008 NHANES 12,758 Age, Sex, Race/Ethnicity
Uribe JA, Swenor BK, et al 2011 Uncorrected Refractive Error in a Latino Population: Proyecto VER 1997–1999 Proyecto VER 4,509 Age, Sex, Race/Ethnicity
Kodjebacheva G, Brown R, et al. 2011 Uncorrected Refractive Error Among First-Grade Students of Different Racial/Ethnic Groups in Southern California: Results a Year After School-Mandated Vision Screening 1999–2006 UCLA MEC 11,332 Age
Tarczy-Hornoch, K., et al 2013 Prevalence and Causes of Visual Impairment in Asian and Non-Hispanic White Preschool Children: Multi-Ethnic Pediatric Eye Disease Study Unknown MEPEDS 1,840 Age, Race / Ethnicity
MEPEDS Group 2009 Prevalence and Causes of Visual Impairment in African-American and Hispanic Preschool Children: the Multi-Ethnic Pediatric Eye Disease Study Unknown MEPEDS 3,207 Age, Race / Ethnicity
Varma R, Wang MY, Ying-Lai M, et al. 2008 The Prevalence and Risk Indicators of Uncorrected Refractive Error and Unmet Refractive Need in Latinos: the Los Angeles Latino Eye Study 2000–2008 LALES 6,129 Age, Sex, Race/Ethnicity
Vitale S, Cotch MF, Sperduto RD. 2006 Prevalence of Visual Impairment in the United States 1999–2002 NHANES 13,265 Age, Sex, Race/Ethnicity
Mansberger SL, Romero FC, et al. 2005 Causes of Visual Impairment and Common Eye Problems in Northwest American Indians and Alaska Natives Unknown Nothwest AIAN 288 Not stratified by demographic variables

Overall Refractive Error Prevalence Rates

Figure 1 below shows estimated prevalence rates for uncorrected refractive error (URE) derived from the selected studies. URE rates ranged from 1.8% in the 2013 MEPEDS study to 15.1% in LALES. The high degree of variation among the results in this figure is likely due to in part to methodological, disease definition, and population differences among the studies. The figure is intended to illustrate the range of published prevalence values; direct comparison of the studies is impossible without considering the underlying differences in the studies. Detailed results from each individual study are available in the full report Published Examination-based Prevalence of Major Eye Disorders.

Figure 1. Overall URE Prevalence Rates in Selected Studies.

Table displays approximate percentages. MESA: 4.5 percent. 2005-2008 NHANES: 3 percent. MEPEDS (Tarczy-Hornoch et al, 2013): 0.5 percent. Proyecto VER: 9.5 percent. MEPEDS (MEPEDS et al, 2009): 1.8 percent. LALES: 15 percent. NHANES: 5 e=percent.

*Age- or population- adjusted prevalence rate.