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Background/aims Cascade screening has been used successfully in relatives of patients with inherited cancers and other genetic diseases to identify presymptomatic disease. This study was designed to examine if this approach would be successful in a high-risk group: firstdegree relatives (FDR) of African-Caribbean glaucoma patients resident in London. Methods African-Caribbean patients (probands) with glaucoma from an inner London hospital setting in a deprived area were asked to disseminate personalised information to their FDR over the age of 30 and to arrange a free hospital-based screening. Data collected, including optical coherence tomography imaging, were reviewed by a glaucoma specialist and if glaucoma was diagnosed or suspected, local specialist referral via family doctor was made. Results 203 probands were recruited from glaucoma clinics. 248 suitable FDR were identified as potentially eligible to attend screening. 57 (23%) FDR made contact with the research team of whom 18 (7%) attended a subsequent screening visit. No patients were diagnosed with glaucoma; one participant was diagnosed as glaucoma suspect. Reasons for poor uptake included reluctance by probands to involve their family members, and retirees spending significant time abroad. Conclusion Cascade screening of FDR of African- Caribbean glaucoma patients in inner city London was unsuccessful. Research confidentiality guidance prohibiting research teams directly contacting family members was a barrier. Greater community engagement, community-based screening and permission to contact FDR directly might have improved uptake. [ABSTRACT FROM AUTHOR]

The phenomenon of contrasting color perceptions of "the dress" photograph has gained scientific interest. The mechanism underlying why individuals differ is yet to be fully explained. We use the powerful twin model design to ascertain the relative contribution of genetic and environmental factors on perception variation. A sample of 466 twins from the British TwinsUK registry were invited to report what color they saw in a standard image of the dress in standard illumination. The mean age of the participants was 49.5 (SD = 17.8) years, and 85% were female. When asked to choose between white and gold (WG) or blue and black (BB), 328 reported WG (70.4%) and 135 (29.0%) reported BB. Subjects choosing WG were significantly older (p < 0.01), but there was no significant difference in gender. Monozygotic (MZ) twins were more concordant in their responses than dizygotic (DZ) twins (0.46 vs. 0.36). Twin modeling revealed that genetic factors accounted for 34% (95% confidence interval, 5%-59%) of variation in the reported color of the dress when adjusted for age, whereas environmental factors contributed 66% (95% CI, 41%-95%). This study suggests environmental factors play a significant role in how an individual perceives the color of "the dress."

Purpose: We estimated the relative importance of genes and environment in dry eye disease (DED) using a classic twin study., Methods: A large sample of 3930 female monozygotic and dizygotic twins from the UK Adult Twin Registry (TwinsUK) was questioned about the presence of a DED diagnosis and about DED symptoms in the preceding 3 months. In addition, a subset of 606 twins was examined for several dry eye signs. Genetic and environmental effects were estimated using maximum likelihood structural equation modeling., Results: All DED outcome variables showed higher correlation in monozygotic twin pairs than in dizygotic twin pairs, suggesting genes have a contributory role in DED. The DED symptoms showed a heritability of 29% (95% confidence interval [CI], 18%-40%). A clinician's diagnosis of DED with concurrent use of artificial tears showed a heritability of 41% (95% CI, 26%-56%). Estimates of the heritability of DED signs were 25% (95% CI, 7%-42%) for interblink interval, 58% (95% CI, 43%-70%) for Schirmer value, 40% (95% CI, 25%-53%) for tear osmolarity, and 78% (95% CI, 59%-90%) for the presence of blepharitis. The unique environment explained the remainder of the variance. We found no significant heritability for tear breakup time., Conclusions: Genetic factors contribute moderately to the diagnosis, symptoms, and the signs of DED. Compared to other ocular phenotypes, the lower heritability might reflect some of the difficulties in objective phenotyping of DED in a population-based sample. However, future genetic studies are now justified and may help in unraveling the pathophysiology of DED., (Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.)