PurposeCongenital achromatopsia (ACHM) is an autosomal recessive disorder in which cone function is absent or severely reduced. Gene therapy in animal models of ACHM have shown restoration of cone function, though translation of these results to humans relies, in part, on the presence of viable cone photoreceptors at the time of treatment. Here, we characterized residual cone structure in subjects with CNGB3-associated ACHM.MethodsHigh-resolution imaging (optical coherence tomography [OCT] and adaptive optics scanning light ophthalmoscopy [AOSLO]) was performed in 51 subjects with CNGB3-associated ACHM. Peak cone density and inter-cone spacing at the fovea was measured using split-detection AOSLO. Foveal outer nuclear layer thickness was measured in OCT images, and the integrity of the photoreceptor layer was assessed using a previously published OCT grading scheme.ResultsAnalyzable images of the foveal cones were obtained in 26 of 51 subjects, with nystagmus representing the major obstacle to obtaining high-quality images. Peak foveal cone density ranged from 7,273 to 53,554 cones/mm2, significantly lower than normal (range, 84,733–234,391 cones/mm2), with the remnant cones being either contiguously or sparsely arranged. Peak cone density was correlated with OCT integrity grade; however, there was overlap of the density ranges between OCT grades.ConclusionsThe degree of residual foveal cone structure varies greatly among subjects with CNGB3-associated ACHM. Such measurements may be useful in estimating the therapeutic potential of a given retina, providing affected individuals and physicians with valuable information to more accurately assess the risk-benefit ratio as they consider enrolling in experimental gene therapy trials. (www.clinicaltrials.gov, NCT01846052.)

IMPORTANCE This study is part of a programmatic effort evaluating the effects of reducing nicotine content of cigarettes to minimally addictive levels. OBJECTIVE To examine whether very low-nicotine-content (VLNC) cigarettes decrease smoking rates and dependence severity among smokers with psychiatric disorders or socioeconomic disadvantage.

High-resolution in vivo imaging has provided evidence of residual cone structure in congenital achromatopsia, although the progressive nature of the disease remains unclear. In this study, the authors use optical coherence tomography and adaptive optics scanning light ophthalmoscopy to investigate longitudinal changes in cone structure in achromatopsia.

BACKGROUND:Researchers in several studies have examined correlations between tobacco harm perceptions and tobacco use in youth, but none have prospectively addressed the association between harm perceptions and subsequent new use across multiple noncigarette products.METHODS: Product-specific absolute and relative harm perceptions for cigarettes, electronic cigarettes (e-cigarettes), cigars, pipes, hookah, and smokeless tobacco were collected at wave 1 (W1) (2013-2014) among youth in the nationally representative US Population Assessment of Tobacco and Health Study (12-17 years of age; n = 10 081). At wave 2 (W2) (2014)(2015), product-specific new use was calculated. Adjusted relative risks were used to estimate if harm perceptions at W1 predicted W2 new tobacco use. RESULTS:The proportion of youth who endorsed "a lot of harm" was highest for cigarettes (84.8%) and lowest for e-cigarettes (26.6%); the proportion of youth who thought products were "more harmful" than cigarettes was highest for cigars (30.6%) and lowest for e-cigarettes (5.1%). Among youth who had not used those products at W1, product-specific new use at W2 ranged from 9.1% (e-cigarettes) to 0.6% (pipes). Youth who believed that noncombustible tobacco products posed "no or little harm" at W1 were more likely to have tried those products at W2 (P < .05). Youth who viewed e-cigarettes, hookah, and smokeless tobacco as "less harmful" than cigarettes at W1 were more likely to try those tobacco products at W2 (P < .05). CONCLUSIONS:Low harm perceptions of noncigarette tobacco products predict new use of these products by youth within the next year. Targeting product-specific harm perceptions may prevent new tobacco use among youth.