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Glaucoma family history, along with age, intraocular pressure and African descent, is among the few definite risk factors for open-angle glaucoma (OAG). The Nottingham Family Glaucoma Screening Study, Sung et al. (20) focused on siblings of white probands with high-tension OAG. An initial examination of 271 siblings (81% participation) using Humphrey perimetry, optic disc assessment and ophthalmologic evaluations, found that 11.8% had OAG and 5.5% were ocular hypertensives/suspects by study criteria. About seven years later, 159 (66%) of siblings without OAG had similar tests; 7% had developed OAG and 19.1% were ocular hypertensives/suspects.
Of note, this study used comprehensive examinations, rather than screening, which typically consists only of simple, rapid tests to identify probable disease. High frequencies of OAG/suspect OAG in siblings were confirmed. The reported estimates of prevalence, incidence and risks are uncertain, however, because of possible effects of small sample sizes, participation biases and attrition. About half of siblings initially diagnosed with OAG had visited optometrists in the previous year, indicating low sensitivity for OAG detection at those visits. The study therefore suggests implementing a formal screening program for siblings, with examinations every two years. While this program may be feasible within the study's setting, its extensive protocol would be costly and not easily implemented. Additionally, considerable supporting data are required to ensure that wide-ranging screening programs are justified. These issues are detailed in the Global AIGS Subcommittee Report on Screening for OAG and the U.K. National Screening Committee Criteria.