Based on a review of studies on the risks and benefits of early screening and treatment for glaucoma, the United States Preventive Services Task Force concluded that it could not recommend for or against screening for asymptomatic adults.
There is insufficient evidence to determine whether adults without vision problems should be screened for glaucoma, the United States Preventive Services Task Force (USPSTF) declared in a statement
published online on July 9, 2013, in the Annals of Internal Medicine
The statement updates recommendations made by the USPSTF in 2004 and was made based on a review of the evidence on benefits, harms, and accuracy of screening and treatment of early glaucoma.
Evaluating the accuracy of screening proved difficult, as there is no standard procedure for glaucoma diagnosis, and screening can include multiple complex tests. The task force assessed evidence from more than 100 studies on the effectiveness of a variety of testing approaches. The evaluation of these tests was further complicated by the lack of an established “gold standard” to assess accuracy. In the absence of such a standard, researchers of the studies included in the review used confirmation of primary open-angle glaucoma (POAG) during a follow-up examination, a diagnosis of POAG that required treatment, and the results of other tests or combinations of tests to gauge the accuracy of the various screening methods. Due to these limitations, the task force was unable to draw conclusions regarding the accuracy of glaucoma screenings.
The task force was unable to find studies that directly evaluated whether screening in asymptomatic adults helped to prevent visual field loss, visual impairment, or worsening quality of life. Nor did the task force find any evidence on the risks of early screening.
More evidence was available on the risks and benefits of early treatment for glaucoma. A systematic review of 10 studies, published in 2007, found that medical treatment protected against worsening of visual field measurements. The task force reviewed 19 additional studies, however, a majority of which found either no change or worsening of visual field measurements with treatment.
Even in longer studies with large populations, the efficacy of glaucoma treatment was unclear. Of 3 large studies with long follow-up periods, 2 concluded that treatment helped to slow the progression of glaucoma, while 1 found no difference between treatment and placebo. A 2005 review of 5 studies, however, found that patients who received medical, surgical, or both forms of treatment had a decreased risk of visual field loss and optic disc damage.
A number of risks associated with glaucoma treatment were identified. Eye redness was the most common adverse effect reported in patients receiving treatment with topical medication, occurring in 2% to 21% of participants, depending on dose, length of use, and medication used. Other adverse effects associated with medication included eye pain, burning, irritation, and dryness, increased iris pigmentation, and cystoid macular edema. Hypotony, hyphema, shallow anterior chambers, cataracts, and choroidal detachment were associated with surgical treatments and occurred more frequently in penetrating procedures.
Screening and treatment were also associated with a risk of over-diagnosis and over-treatment as patients with increased intraocular pressure, once thought to be the hallmark sign of the condition, do not always have glaucoma.
Based on the inconclusive evidence it found, the task force concluded that it could not make a recommendation for or against glaucoma screening in asymptomatic adults. More research on the progression of the condition and on treatment is needed before suggestions on early screening and treatment can be made, the statement notes.
Until then, the American Academy of Ophthalmology recommends medical eye evaluations, including tests for glaucoma, for all adults, with frequency depending on age and other risk factors. In addition, the American Optometric Association recommends eye examination every 1 to 2 years depending on individual risk.