ArticleDer Ophthalmologe : Zeitschrift der Deutschen Ophthalmologischen Gesellschaft2020
[Statistical analysis of correlated measurement data in ophthalmology : Tutorial for the application of the linear mixed model in SPSS and R using corneal biomechanical parameters].
Article in Der Ophthalmologe : Zeitschrift der Deutschen Ophthalmologischen Gesellschaft, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 11 papers.
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11 citing papers in PubMed.
- Assessment of the impact of cataract surgery on subjective quality of vision across different intraocular lens type using the portuguese-validated QoV questionnaire.International ophthalmology · 2026Article
- Objective assessment of graft clarity and recurrence after penetrating keratoplasty for granular, lattice and macular corneal dystrophy using scheimpflug densitometry.Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie · 2026Article
- A simplified slipknot technique for pupilloplasty in the treatment of mydriasis.International journal of ophthalmology · 2026Article
- Nanoindentation under retrocorneal pressure to determine the biomechanical response of the human cornea to accelerated UVA crosslinking and riboflavin osmolarity ex vivo.Scientific reports · 2025Article
- Investigating colour vision and its structural correlates 15 years following a first demyelinating event.Journal of neurology, neurosurgery, and psychiatry · 2025Article
- Clostridium butyricum regulates intestinal barrier function via trek1 to improve behavioral abnormalities in mice with autism spectrum disorder.Cell & bioscience · 2024Article
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- What do windsurfers and kitesurfers in Germany know about surfer's ear and how is it influenced by protective measures?The Journal of laryngology and otology · 2024Article
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- Orthokeratology Lens Wear for 2 Years in Children Did Not Alter Tear Film Lipid Thickness by Non-Invasive Interferometry.Frontiers in medicine · 2022Article
- Association between Corneal Stiffness Parameter at the First Applanation and Keratoconus Severity.Journal of ophthalmology · 2020Article
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7 authors.
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Abstract
backgroundIn ophthalmology data from both eyes of a person are frequently included in statistical analyses. As correlated data are used this procedure contradicts the independency principle for classical statistical tests, such as Student's t‑test and analysis of variance (ANOVA). In this tutorial a new possibility is presented in which data from both eyes can be used for statistical analysis.
objectiveThe statistical approach of linear mixed models (LMM) was used to take correlated data of both eyes of patients into account.
methodsThe LMM is available in several statistical software packages, e.g. SPSS and R, and allows the inclusion of measurement data from both eyes of a person in the statistical analysis. The application was tested on data from a biomechanical characterization of the cornea from healthy participants assessed with the dynamic Scheimpflug analyzer (Corvis ST; Oculus, Wetzlar, Germany).
resultsA total of 158 eyes from 79 healthy participants were included. A strong correlation between the right and left eyes of the participants could be observed with respect to the analyzed parameters. Comparison of the biomechanical parameters between the different age groups showed that P-values were increased when using the LMM compared to the ANOVA. Older participants (56-79 years) showed a significantly shorter time to the second applanation (P = 0.002), a significantly increased eyeball movement during the deformation (P = 0.001) and a significantly higher stiffness at the first applanation (P = 0.006) compared to younger participants (18-35 years).
conclusionThe analysis of measurement data from both eyes using classical statistical tests, without the consideration of the correlation, leads to an overestimation of the statistical power. This can be avoided by implementation of the LMM.
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