Publisher's Synopsis
Impaired visual acuity is common in older adults. In addition to a higher incidence and prevalence of primary ocular disease and systemic diseases associated with ocular disease in older compared to younger adults, older adults also experience normal age-related changes in vision. Because symptoms may be relatively mild or progress slowly, older adults may be unaware of or underreport impaired visual acuity. Older adults may also have difficulty recognizing or reporting impaired visual acuity due to the presence of co-morbidities such as cognitive impairment. Screening for vision disorders could help identify impaired visual acuity in older adults and lead to treatments that improve quality of life or functional capacity, or prevent or slow down progression of vision loss. In 2008, the U.S. Preventive Services Task Force commissioned an evidence review on screening for impaired visual acuity in older adults, in order to inform an updated USPSTF guideline. The main purpose of the evidence review is to evaluate new evidence published on screening for impaired visual acuity in older adults. Impaired visual acuity refers to decreased clarity or sharpness of vision. In addition to decreased visual acuity, vision impairment can also be associated with decreases in low light vision, color vision, binocularity, contrast sensitivity, or stereopsis, as well as visual field loss (areas in the field of view in which objects cannot be seen). Visual acuity is most commonly assessed using the Snellen eye chart, which assesses the ability of patients to recognize letters of different sizes arranged in rows from a pre-specified distance (typically 20 feet). The severity of decreased visual acuity varies. Vision impairment has been defined as visual acuity of worse than 20/40 or 20/50 but better than 20/200 (the threshold for legal blindness). In this report, we use the term "impaired visual acuity" rather than "vision impairment" because the latter term implies functional limitations. In addition, vision impairment could occur for reasons other than visual acuity loss. Visual acuity worse than 20/20 but better than 20/40 or 20/50 is thought to have minimal effects on reading ability, functional capacity, or quality of life. Although no standardized definition for "mild" impairment in visual acuity exists, some studies have used a definition of visual acuity between roughly 20/40 and 20/80.This degree of impaired visual acuity is less likely to cause major functional limitations than more severe impairment in visual acuity, and may be more apt to be identified through screening. This report focuses on impaired visual acuity associated with the following conditions: uncorrected refractive errors, cataracts, and age-related macular degeneration (ARMD). Diabetic retinopathy and glaucoma are addressed elsewhere by the USPSTF. Screening approaches for glaucoma differ from the screening tests typically used in primary care settings for the conditions included in this report. Screening for diabetic retinopathy typically occurs in the context of care for patients with known diabetes. The KQs are: KQ1: Does vision screening in asymptomatic older adults result in improved morbidity or mortality or improved quality of life? KQ2: Are there harms of vision screening in asymptomatic older adults? KQ3: What is the accuracy of screening for early impairment in visual acuity due to uncorrected refractive error, cataracts or age-related macular degeneration? KQ4: Does treatment of early impairment in visual acuity due to uncorrected refractive error, cataracts or age-related macular degeneration lead to improved morbidity/mortality, or quality of life? KQ5: Are there harms of treating early impairment in visual acuity due to uncorrected refractive error, cataracts or age-related macular degeneration?
