new US preventive service task force guidelines on screening asymptomatic individuals for glaucoma (see link: http://www.uspreventiveservicestaskforce.org/uspstf13/glaucoma/glaucomafinalrs.pdf
bottom line:
–open-angle glaucoma is common (2% of those >40yo)
–significant concerns about diagnostic criteria — turns out that many people with high intraocular pressures (IOP) do not have glaucoma on sophistocated (and expensive) testing, and some with glaucoma have normal IOP.
–data are pretty good/consistent that treating people with high IOP and early glaucoma/vision loss have improved visual outcomes with glaucoma therapy. but hard to predict which people with high IOP would progress to visual field loss
–but no compelling data (and not many studies…) finding that screening asymptomatic population is useful. and downside of treatment is real (cataracts, complications of surgery or medications)
–so, recommendation is: there are insufficient data to make a recommendation. american academy of ophthalmopathy suggests screening (as part of comprehesnive eye exam) with frequency depending on age and glaucoma risk factors (which are age, fam hx, African-American, maybe Latino). american optometric society recommends screening every 1-2 years
sounds to me like there really are not sufficient data to make a clear recommendation, given lack of conclusive data and evident (though small %) of harms. the concern to me is that there are data in those people with high IOP and early glaucoma that treatment lowers risk of further deterioration of visual fields, that glaucoma is a slowly progressive disease (and, as such, would need very long studies to show that treating a 40 year old decreases poor vision or blindness at age 70), and that it is probably remarkably unreliable and late in the course to wait for patients to notice field defects (my experience is that patients can have pretty large defects in one eye and barely notice anything). so, to present this more broadly– this really raises the baseline issue for so much of what we do in primary care: what should clinical practice be when something makes some sense physiologically (high IOP is often bad for longterm vision, but probably not always), there are some positive intervention-type studies (treating those with high IOP and glaucoma/visual field defects decreases further visual field defects), the adverse effects of treatment are real but small, however there are no clear rigorous data to support an aggressive program of screening??? on this issue i tend to support the screening (since preventing loss of vision in older people is so important to their quality and quantity of life), though when i teach residents i will more clearly enunciate the lack of clear-cut data.
geoff