Background/Aim: Experimental studies have identified differences in the effect of physicochemical properties of beverages on the etiology of erosive tooth wear (ETW). Little is known from epidemiological studies about the relationship between ETW and consumption of juices, drinks and milk. This study examined the relationship between the consumption of juices, drinks, milk and ETW in children in the United States. Methods: The National Health and Nutrition Examinations Survey data for 2003–2004 was analyzed. Trained and calibrated examiners used the modified Smith and Knight Tooth Wear Index from a 1998 United Kingdom Adult Health Survey to measure ETW. Beverage consumption collected via a Food Frequency Questionnaire was processed with Diet*Calc software to obtain the average daily consumption frequency for all queried juice categories, milk and carbonated beverages. Survey-weighted descriptive and multivariable analyses were performed. Results: Prevalence of ETW was highest in children aged 18–19 years (56%), males (49%), and lowest in Blacks (31%). Milk and soft drinks (0.85 times a day) and fruit drinks (0.69) were the most consumed products by children. Children with ETW had significantly higher odds of being frequent consumers of apple juice after adjusting for age, gender, and race/ethnicity. Blacks had the highest mean daily apple juice consumption, but the mean difference between those with ETW and those without ETW was not significant. Conclusion: ETW was associated with frequent intake of apple juice, but the mean difference in consumption between groups with ETW versus those without ETW within racial/ethnic groups was not significant.

PurposeTo assess reliability and repeatability of cone density measurements by using confocal and (nonconfocal) split-detector adaptive optics scanning light ophthalmoscopy (AOSLO) imaging. It will be determined whether cone density values are significantly different between modalities in Stargardt disease (STGD) and retinitis pigmentosa GTPase regulator (RPGR)–associated retinopathy.MethodsTwelve patients with STGD (aged 9–52 years) and eight with RPGR-associated retinopathy (aged 11–31 years) were imaged using both confocal and split-detector AOSLO simultaneously. Four graders manually identified cone locations in each image that were used to calculate local densities. Each imaging modality was evaluated independently. The data set consisted of 1584 assessments of 99 STGD images (each image in two modalities and four graders who graded each image twice) and 928 RPGR assessments of 58 images (each image in two modalities and four graders who graded each image twice).ResultsFor STGD assessments the reliability for confocal and split-detector AOSLO was 67.9% and 95.9%, respectively, and the repeatability was 71.2% and 97.3%, respectively. The differences in the measured cone density values between modalities were statistically significant for one grader. For RPGR assessments the reliability for confocal and split-detector AOSLO was 22.1% and 88.5%, respectively, and repeatability was 63.2% and 94.5%, respectively. The differences in cone density between modalities were statistically significant for all graders.ConclusionsSplit-detector AOSLO greatly improved the reliability and repeatability of cone density measurements in both disorders and will be valuable for natural history studies and clinical trials using AOSLO. However, it appears that these indices may be disease dependent, implying the need for similar investigations in other conditions.

PurposeTo characterize sources of inter- and intrasubject variability in quantitative foveal avascular zone (FAZ) metrics.MethodsTwo 3×3-mm optical coherence tomography angiography scans (centered on the fovea) were acquired in both eyes of 175 subjects. An image of the superficial plexus was extracted from each scan and segmented twice by a single observer. Four quantitative FAZ morphology metrics (area, axis ratio, acircularity, major horizontal axis angle) were calculated, and a variance components analysis was performed.ResultsMean (±SD) age was 27.9 ± 11.9 years, and 55% were female. Area had the largest amount of variance resulting from intersubject differences (93.1%). In contrast, there was large interocular variance for axis ratio, acircularity, and major horizontal axis angle (55.0%, 53.7%, 70.7%, respectively), though only axis ratio showed significant asymmetry between fellow eyes (P < 0.05). Neither repeated images from the same eye nor repeated segmentation on the same image were significant sources of variance.ConclusionsMetrics of FAZ morphology show excellent repeatability and reliability. Excluding FAZ area, there was a high amount of variance attributed to interocular differences for the other FAZ metrics; therefore, the fellow eye should not be considered a control for FAZ studies when using these metrics.Translational RelevanceVision scientists must be prudent when choosing FAZ metrics, as they display varying degrees of within-subject differences relative to between-subject differences. It seems likely that different metrics will be best suited for different tasks, such as monitoring small changes over time within a single subject or assessing whether a given FAZ is abnormal.

BackgroundAdaptive optics scanning light ophthalmoscopy (AOSLO) enables direct visualisation of the cone mosaic, with metrics such as cone density and cell spacing used to assess the integrity or health of the mosaic. Here we examined the interobserver and inter-instrument reliability of cone density measurements.MethodsFor the interobserver reliability study, 30 subjects with no vision-limiting pathology were imaged. Three image sequences were acquired at a single parafoveal location and aligned to ensure that the three images were from the same retinal location. Ten observers used a semiautomated algorithm to identify the cones in each image, and this was repeated three times for each image. To assess inter-instrument reliability, 20 subjects were imaged at eight parafoveal locations on one AOSLO, followed by the same set of locations on the second AOSLO. A single observer manually aligned the pairs of images and used the semiautomated algorithm to identify the cones in each image.ResultsBased on a factorial study design model and a variance components model, the interobserver study's largest contribution to variability was the subject (95.72%) while the observer's contribution was only 1.03%. For the inter-instrument study, an average cone density intraclass correlation coefficient (ICC) of between 0.931 and 0.975 was calculated.ConclusionsWith the AOSLOs used here, reliable cone density measurements can be obtained between observers and between instruments. Additional work is needed to determine how these results vary with differences in image quality.

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PurposeDirectional optical coherence tomography (D-OCT) allows the visualization of the Henle fiber layer (HFL) in vivo. Here, we used D-OCT to characterize the HFL and outer nuclear layer (ONL) in albinism and examine the relationship between true foveal ONL and peak cone density.MethodsHorizontal D-OCT B-scans were acquired, registered, and averaged for 12 subjects with oculocutaneous albinism and 26 control subjects. Averaged images were manually segmented to extract HFL and ONL thickness. Adaptive optics scanning light ophthalmoscopy was used to acquire images of the foveal cone mosaic in 10 subjects with albinism, from which peak cone density was assessed.ResultsAcross the foveal region, the HFL topography was different between subjects with albinism and normal controls. In particular, foveal HFL thickness was thicker in albinism than in normal controls (P < 0.0001), whereas foveal ONL thickness was thinner in albinism than in normal controls (P < 0.0001). The total HFL and ONL thickness was not significantly different between albinism and controls (P = 0.3169). Foveal ONL thickness was positively correlated with peak cone density in subjects with albinism (r = 0.8061, P = 0.0072).ConclusionsFoveal HFL and ONL topography are significantly altered in albinism relative to normal controls. Our data suggest that increased foveal cone packing drives the formation of Henle fibers, more so than the lateral displacement of inner retinal neurons (which is reduced in albinism). The ability to quantify foveal ONL and HFL may help further stratify grading schemes used to assess foveal hypoplasia.

Objective: The retina is an extension of the central nervous system (CNS), and ocular symptoms can precede manifestations of CNS disorders. Given that several neurodegenerative conditions that affect the brain exhibit ocular symptoms, the retina may be an accessible biomarker to monitor disease progression. Dopamine, the key neurotransmitter related to Parkinson’s disease (PD), is contained in amacrine and interplexiform cells, which reside in specific retinal layers. Understanding how loss of dopaminergic cells affects retinal anatomy could be relevant for monitoring disease progression. Here, our objective is to evaluate retinal structure (foveal pit morphology and thickness) in patients with PD. Methods: Thirty-three Caucasian subjects diagnosed with PD and 40 age-matched Caucasian control subjects underwent retinal imaging with spectral-domain optical coherence tomography (SD-OCT). Axial length measurements were used to correct the lateral scale of each macular volume scan. From these corrected volumes, foveal morphology was quantified with previously described algorithms, and Early Treatment Diabetic Retinopathy Study (ETDRS) grids of retinal thickness were generated and incorporated into a logistic regression model to predict PD. Results: Interocular foveal morphology measurements were highly symmetrical in PD patients and control subjects. There were no significant differences in foveal pit morphology between PD patients and control subjects. Using a model incorporating sex and axial length corrected ETDRS regions, we generated a receiver operating characteristic curve with a C-statistic of 0.80. Conclusion: Our study, which to our knowledge is the first to properly scale OCT measurements when quantifying retinal thickness, demonstrates that PD patients retain foveal symmetry between eyes. When constructing a model to predict PD, sex, along with the center 1 mm and temporal outer ETDRS regions, were significant predictors of PD. In addition to proper scaling of OCT measures, gender and racial differences in retinal anatomy should be considered in building future predictive PD models when using OCT.

Objective To examine longitudinal trends and associated factors in dental service utilization by adolescents progressing to early adulthood in the United States. Data Source The National Longitudinal Study of Adolescent Health from Waves I (1994-95), II (1996), III (2001-2002) and IV (2007-2008). Study Design This is a retrospective, observational study of adolescents' transition to early adulthood. We obtained descriptive statistics and performed logistic regression analyses to identify the effects of baseline and concurrent covariates on dental service utilization from adolescence to early adulthood over time. Principal Findings Dental service utilization within the prior 12 months peaked at age 16 (72%), gradually decreased until age 21 (57%), and thereafter remained flat. Whites and Asians had a 10-20 percentage points higher proportion of dental service utilization at most ages compared to Blacks and Hispanics. Dental service utilization at later follow-up visits was strongly associated with baseline utilization with OR= 10.7, 2.4 and 1.5 at the 1-year, 7-year and 13-year follow-ups respectively. These effects decreased when adjusted for current income, insurance and education. Compared to Whites, Blacks were consistently less likely to report any dental examination. Conclusion Dental service utilization was highest in adolescents. Gender, education, health insurance and income in young adulthood were significant predictors of reporting a dental examination. Blacks had lower odds of reporting a dental examination either as adolescents or as young adults.