Ophthalmic statistics note 1: unit of analysis

Bunce, Catey; Patel, Krishna; Xing, Wen; Freemantle, Nick; Doré, Caroline J

doi:10.1136/bjophthalmol-2013-304587

Cited by 38 publications

(40 citation statements)

References 13 publications

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“…To avoid statistical problems with independent sampling, we selected only one eye for data collection: the eye with the best image quality, and if of equal quality then the right eye [13]. Images were examined in Heidelberg Eye Explorer 1.9.10.0 (Heidelberg Engineering, Heidelberg, Germany).…”

Section: Methodsmentioning

confidence: 99%

Effect of aging and lifestyle on photoreceptors and retinal pigment epithelium: cross-sectional study in a healthy Danish population

Harris

Subhi

Sørensen

2017

Pathobiology of Aging & Age-related Diseases

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Photoreceptors and their supporting retinal pigment epithelium constitute the key functional parts of the retina. Here, a study was undertaken to show how aging and lifestyle factors affect the photoreceptor layer and the retinal pigment epithelium and Bruch’s membrane complex (RPE-BM) in vivo in a healthy Danish population using spectral-domain optical coherence tomography. This was a cross-sectional study of healthy humans aged ≥50 years. All participants were interviewed for medical history and lifestyle factors. Maculae of all participants were scanned using spectral-domain optical coherence tomography. The thickness of the photoreceptor layer and the RPE-BM was measured on one eye from each participant. In 150 eyes of 150 participants, it was found that aging was associated with a decrease in the thickness of the photoreceptor layer (−0.143 μm/year, P = 0.031) and an increase in the thickness of the RPE-BM layer (0.100 μm/year, P = 0.029) at the foveal minimum. Regarding lifestyle factors, alcohol intake or BMI were not associated with any significant trend, but physical inactivity and smoking had effects on the photoreceptor layer (decreased thickness) and the RPE-BM layer (increased thickness) indicating an accelerated aging process of the macula. Taken together, aging affects photoreceptors and the RPE-BM, and these aging trends are accelerated in smokers and the physically inactive.

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Section: Methodsmentioning

confidence: 99%

Effect of aging and lifestyle on photoreceptors and retinal pigment epithelium: cross-sectional study in a healthy Danish population

Harris

Subhi

Sørensen

2017

Pathobiology of Aging & Age-related Diseases

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“…27,28 Comparisons between groups or variables were performed using the non-parametric Mann-Whitney U-test or Kruskal-Wallis H-test, and correlations in cross tables were derived using the Pearson's Χ 2 -test. To correct for multiple testing, we adjusted all P-values following Eye the Benjamini-Hochberg procedure.…”

Section: Statistical Analysesmentioning

confidence: 99%

Spectral-domain optical coherence tomography findings of the macula in 500 consecutive patients with uveitis

Grajewski

Boelke

Adler

et al. 2016

Eye

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Purpose To analyze the macular structure in a large series of consecutive patients with different types of uveitis using spectraldomain optical coherence tomography (SD-OCT). Patients and methods Five hundred eyes of 500 consecutive patients with anterior, intermediate, posterior, and panuveitis underwent standardized macular examination using SD-OCT. Central retinal thickness (CRT), macular volume (MV), and presence of cystoid macular edema (CME), diffuse macular edema (DME), serous retinal detachment (SRD), epiretinal membrane with (ERM+) and without (ERM − ) retinal surface wrinkling were determined. Results The anatomic location of inflammation affected significantly CRT and MV (Po0.001, respectively), with the highest values in intermediate and panuveitis. CME was seen in 25% of all uveitic eyes, DME in 11%, SRD in 8%, ERM+ in 18%, and ERM − in 13%. CME was most frequent in intermediate (40%) and panuveitis (36%); DME was most frequent in panuveitis (18%) and posterior uveitis (17%); SRD was most frequent in panuveitis (15%) and posterior uveitis (10%); ERM+ was most frequent in panuveitis (45%) and intermediate uveitis (30%); and ERM − was most frequent in intermediate (14%) and posterior uveitis (15%). Conclusion SD-OCT of the macula is recommended for all uveitis patients. CRT, MV, and the incidence of CME were highest in intermediate and panuveitis.

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“…1,2 An important issue in ophthalmology research is that a substantial number of articles in ophthalmology journals give the study outcomes in either eye of a study patient as an independent data point. Although this important limitation was highlighted in a number of publications, [3][4][5][6][7] we had the observation that such improper statistical testing still continued to appear even in high-impact-factor journals.…”

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confidence: 99%