June 10, 2022, 8:35 a.m. News Staff — On May 24, the U.S. Preventive Services Task Force posted a final recommendation statement, final evidence review and evidence summary on screening for primary open-angle glaucoma in adults, as well as a final recommendation statement, final evidence review and evidence summary on screening for impaired visual acuity in older adults.
Based on a review of the evidence, the task force concluded that the current evidence is insufficient to assess the balance of benefits and harms of screening for either of these conditions, and issued a pair of “I” recommendations.
The recommendation on screening for impaired visual acuity applies to asymptomatic adults 65 or older; it does not apply to people who have reported signs and symptoms of vision loss, are seeking care for vision problems, or have vision loss related to another medical condition.
The recommendation on screening for glaucoma, meanwhile, applies to asymptomatic adults 40 or older; it does not apply to those who have reported signs and symptoms of vision loss or who have been diagnosed with other types of glaucoma.
“Although impaired vision is a common condition in older adults that can affect independence and quality of life, there is not enough evidence to recommend for or against primary care clinicians screening for the condition in people who have not noticed problems with their vision,” remarked task force member Katrina Donahue, M.D., M.P.H., professor and vice chair of research in the Department of Family Medicine at the University of North Carolina at Chapel Hill School of Medicine, in a USPSTF Bulletin. “In the absence of this evidence, primary care clinicians should use their judgment when deciding whether or not to screen.”
“The task force wanted to see if there was an opportunity for primary care clinicians to play a greater role in helping to prevent vision loss from glaucoma, especially among those who are disproportionately affected,” added USPSTF Chair Carol Mangione, M.D., M.S.P.H. “However, there is not enough evidence to inform what primary care clinicians can do, so we are calling for more research.”
Open-angle glaucoma is the most common form in the United States and occurs in about 90% of people who have glaucoma. According to the National Eye Institute, open-angle glaucoma is responsible for nearly 20% of all cases of blindness in African Americans; people with diabetes or high blood pressure, and those with a family history of the condition, also are at increased risk.
Impaired visual acuity — defined by the USPSTF as best corrected visual acuity worse than 20/40 but better than 20/200 — refers to vision that is blurry, distorted or otherwise not normal and may be caused by glaucoma as well as other conditions such as cataracts and macular degeneration. According to the CDC’s Vision and Eye Health Surveillance System, about 6 million Americans had vision loss in 2017, the last year for which data are available. VEHSS data also indicate that the condition is more prevalent in women and in people 65 and older and that the risk of vision loss is higher in Hispanic/Latino and Black individuals than in white individuals.
The final recommendation statements replace recommendations issued by the task force on glaucoma and impaired visual acuity in 2013 and 2016, respectively. The 2013 recommendation found insufficient evidence to assess the balance of benefits and harms of screening for primary open-angle glaucoma in adults; similarly, the 2016 recommendation stated that there was insufficient evidence to assess the balance of benefits and harms of screening for visual acuity to improve outcomes in older adults.
The AAFP supported both earlier recommendations.
To update these recommendations, the task force commissioned a pair of reviews to determine the benefits and harms of screening for glaucoma in adults and the benefits and harms of screening for impaired visual acuity in older adults.
For glaucoma, the evidence review focused on screening for primary open-angle glaucoma; screening for and treatment of other forms of the condition were outside the review’s scope.
For impaired visual acuity, the evidence review focused on screening for impaired visual acuity associated with uncorrected refractive errors, cataracts and AMD, as well as treatment of AMD. The task force also stated that because the benefits and harms related to treatment of uncorrected refractive errors and cataracts has been previously established, it was not addressed in the current review.
Data sources for the evidence review on glaucoma screening included studies published in the Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews and the Medline database through Feb. 9, 2021, with additional surveillance conducted through Jan. 21, 2022. Investigators also reviewed studies from previous reports and reference lists. A total of 83 studies were included in the evidence review, 67 of which were new.
The task force found that direct evidence on the benefits of screening vs. no screening was limited. Although some screening tests such as optical coherence testing and visual field assessment showed “reasonable accuracy” in identifying people with open-angle glaucoma, there was limited evidence on other tests such as optic disc photography, pachymetry and telemedicine. Overall, there were no benefits from screening on vision-related quality of life or function or fall risk.
Topical medical treatments and surgical procedures such as laser trabeculoplasty for ocular hypertension or untreated open-angle glaucoma were associated with reductions in intraocular pressure and reduced risk of glaucoma progression. However, there was limited evidence that treatment improved health outcomes such as vision-related function and quality of life or evidence that improvements in intermediate outcomes could lead to improvements in health outcomes.
Data sources for the evidence review on impaired visual acuity also included studies from the Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews and the Medline database through Feb. 9, 2021, with additional surveillance conducted through Jan. 21, 2022. Investigators also reviewed studies from prior reports and manually reviewed reference lists. Of 25 studies reviewed, eight were new, and the systematic review used for the 2016 recommendation review was updated with six new trials.
Compared with a complete ophthalmological examination for identifying visual conditions, visual acuity tests had poor diagnostic accuracy. Evidence on the accuracy of other screening methods, such as computerized screening tools, Minimum Data Set Vision Patterns scores and mobile apps, was limited. In addition, screening questions were not accurate in identifying people at increased risk for impaired visual acuity due to uncorrected refractive errors, cataracts or AMD compared with a visual acuity eye chart.
With regard to early detection and treatment, results from four trials that compared screening vs. no screening, usual care or delayed screening on vision and other clinical outcomes found no differences in visual acuity, likelihood of vision disorders or vision-related functional impairment.
For wet AMD, results from four trials that compared injections of vascular endothelial growth factor inhibitors with placebo or no treatment found that VEGF inhibitors were effective in improving visual acuity-related outcomes. Three trials compared the effectiveness of VEGF inhibitors aflibercept and ranibizumab; results from two of these trials found that they were associated with similar improvements in vision-related function.
For dry AMD, a systematic review of 19 trials found that antioxidant multivitamins were associated with decreased risk of progression to late AMD and more than three lines of visual acuity loss compared with placebo. Other evidence indicated that zinc was associated with a decreased risk of progression to late AMD, and that compared with placebo, the combination of antioxidants and zinc reduced the risk of progression to advanced AMD and visual acuity loss in a subset of patients.
Other potential therapies (e.g., lutein, vitamin E and various antioxidant multivitamin and mineral combinations) showed no clear effects on AMD progression or visual acuity, and evidence on other health outcomes such as cognition and vision-related function and quality of life was limited.
No studies on the harms of screening for visual impairment in a primary care setting were available.
Draft recommendation statements on screening for each condition were posted on the USPSTF website from Oct. 26, 2021, to Nov. 22, 2021.
Regarding screening for impaired visual acuity, several commenters asked why the task force’s review included evidence on screening for uncorrected refractive error, cataracts and AMD but limited its review on treatment to wet and dry AMD. In response, the USPSTF added clarifying language in the Supporting Evidence section stating that because the evidence on treatment of cataracts and refractive error is well established, the task force limited its review to the benefits and harms of treatment of wet and dry AMD. When asked why other conditions such as diabetic retinopathy and glaucoma were not addressed in the recommendation, the USPSTF explained that screening for glaucoma is covered in a separate recommendation, and that although diabetic retinopathy is a common cause of blindness, surveillance for the condition is considered part of diabetes management and thus outside the scope of the recommendation.
As for screening for glaucoma, the task force received a number of comments asking why the USPSTF found insufficient evidence to recommend screening, given that there are accurate screening tools and effective treatments for glaucoma. The task force explained that athough it has found adequate evidence that screening tests can identify primary open-angle glaucoma, these tests are not commonly found in primary care settings. The task force also stated that evidence that treatment of primary open-angle glaucoma directly improves health outcomes or that changes in intermediate outcomes result in improved health outcomes was limited.
Several commenters asked why the task force did not recommend screening in Black and Hispanic/Latino individuals given the high prevalence of glaucoma in these populations. The USPSTF responded that although it recognizes that glaucoma disproportionately affects these patients, it did not find adequate evidence on screening in these groups, adding that evidence on ways to help identify people at increased risk who could benefit from screening is lacking. The task force also called for more studies that target higher-risk populations.
The AAFP’s Commission on Health of the Public and Science will review the task force’s final recommendation statements, final evidence reviews and evidence summaries and determine the Academy’s stance on each recommendation.