Publications by authors named "Katharina Breher"

7 Publications

  • Page 1 of 1

Comparison of Methods for Estimating Retinal Shape: Peripheral Refraction vs. Optical Coherence Tomography.

J Clin Med 2021 Jan 6;10(2). Epub 2021 Jan 6.

Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany.

Retinal shape presents a clinical parameter of interest for myopia, and has commonly been inferred indirectly from peripheral refraction (PRX) profiles. Distortion-corrected optical coherence tomography (OCT) scans offer a new and direct possibility for retinal shape estimation. The current study compared retinal curvatures derived from OCT scans vs. PRX measurements in three refractive profiles (0° and 90° meridians, plus spherical equivalent) for 25 participants via Bland-Altman analysis. The radial differences between both procedures were correlated to axial length using Pearson correlation. In general, PRX- and OCT-based retinal radii showed low correlation (all intraclass correlation coefficients < 0.21). PRX found flatter retinal curvatures compared to OCT, with the highest absolute agreement found with the 90° meridian (mean difference +0.08 mm) and lowest in the 0° meridian (mean difference +0.89 mm). Moreover, a negative relation between axial length and the agreement of both methods was detected especially in the 90° meridian (R = -0.38, = 0.06). PRX measurements tend to underestimate the retinal radius with increasing myopia when compared to OCT measurements. Therefore, future conclusions from PRX on retinal shape should be made cautiously. Rather, faster and more clinically feasible OCT imaging should be performed for this purpose.
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http://dx.doi.org/10.3390/jcm10020174DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7825350PMC
January 2021

Choroidal Biomarkers: A Repeatability and Topographical Comparison of Choroidal Thickness and Choroidal Vascularity Index in Healthy Eyes.

Transl Vis Sci Technol 2020 10 8;9(11). Epub 2020 Oct 8.

Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.

Purpose: Choroidal thickness (ChT) and choroidal vascularity index (CVI) represent two important metrics in health-, disease-, and myopia-related studies. Wide-field swept-source optical coherence tomography (OCT) provides improved and extended imaging and extraction of choroidal variables. This study characterizes the topography and repeatability of these parameters in healthy eyes.

Methods: Swept-source OCT volume scans were obtained on 14 young adult patients on three separate days. ChT and CVI were automatically corrected for image magnification and extracted for different enface regions within an extended ETDRS grid of 10 mm diameter. Topographical distribution, correlation to ocular length, and intersession repeatability of both choroidal parameters were assessed.

Results: CVI showed little fluctuation between subfields, unlike ChT, which demonstrated thinning toward the peripheral choroid (coefficients of variation 5.92 vs. 0.89). ChT showed a consistent negative correlation with axial length (ρ = -0.05 to -0.61), although this was only statistically significant in the inner superior subfield ( = 0.02). There was no consistent or significant relationship between CVI and axial length or between CVI and ChT. The repeatability of CVI measurements (3.90%-5.51%) was more consistent between scan regions than ChT measurements (10.37-20.33 µm).

Conclusions: CVI values were consistent across the central 10 mm of the retina, while ChT reduced with eccentricity. The repeatability of both parameters is similar to the effect size reported in many studies using the choroid as a biomarker, which should be considered in the interpretation of findings.

Translational Relevance: This study provided normative as well as metrological information for the clinical interpretation of ChT and CVI in health and disease.
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http://dx.doi.org/10.1167/tvst.9.11.8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7552934PMC
October 2020

Myopia induces meridional growth asymmetry of the retina: a pilot study using wide-field swept-source OCT.

Sci Rep 2020 07 2;10(1):10886. Epub 2020 Jul 2.

Institute for Ophthalmic Research, Eberhard Karls University Tuebingen, 72076, Tübingen, Germany.

Myopic axial eye growth has mechanical implications on ocular structures, such as the retinal and foveal shape integrity or choroidal thickness. The current study investigated myopia-related changes of retinal radius of curvature, foveal width, depth, slope and choroidal thickness. Wide-field swept-source OCT line and volume scans were performed on 40 young adult participants in horizontal and vertical directions. OCT scans were corrected for their scan display distortions before automated extraction of retinal and foveal shape parameters. All findings were correlated to refractive error and axial length. The horizontal retinal radius of curvature and the directional ratio between horizontal and vertical retinal shape correlated significantly with axial length ([Formula: see text] and [Formula: see text]). Vertical retinal shape and foveal pit parameters neither showed any significant correlations with axial length nor refractive error (all [Formula: see text] 0.05). Choroidal thickness correlated significantly with refractive error in all analyzed regions ([Formula: see text]), but less with axial length ([Formula: see text] to - 0.37). Horizontal retinal shape and choroidal thickness, but not foveal pit morphology, were altered by myopic eye growth. Asymmetries in horizontal versus vertical retinal shape with increasing myopia were detected. These parameters could act as promising biomarkers for myopia and its associated complications.
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http://dx.doi.org/10.1038/s41598-020-67940-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7331682PMC
July 2020

To Correct or Not Correct? Actual Evidence, Controversy and the Questions That Remain Open.

J Clin Med 2020 Jun 24;9(6). Epub 2020 Jun 24.

Carl Zeiss Vision International GmbH, ZEISS Group, Turnstrasse 27, 73430 Aalen, Germany.

Clinical studies and basic research have attempted to establish a relationship between myopia progression and single vision spectacle wear, albeit with unclear results. Single vision spectacle lenses are continuously used as the control group in myopia control trials. Hence, it is a matter of high relevance to investigate further whether they yield any shift on the refractive state, which could have been masked by being used as a control. In this review, eye development in relation to eyes fully corrected versus those under-corrected is discussed, and new guidelines are provided for the analysis of structural eye changes due to optical treatments. These guidelines are tested and optimised, while ethical implications are revisited. This newly described methodology can be translated to larger clinical trials, finally exerting the real effect of full correction via single vision spectacle lens wear on eye growth and myopia progression.
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http://dx.doi.org/10.3390/jcm9061975DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7356996PMC
June 2020

A metrological approach to the analysis of choroidal thickness by optical coherence tomography 3D scans in myopia research.

Sci Rep 2019 12 30;9(1):20322. Epub 2019 Dec 30.

Institute for Ophthalmic Research, Eberhard Karls University Tuebingen, Tuebingen, 72076, Germany.

In myopia research, changes of choroidal thickness in response to optically induced signals serve as predictor for changes in axial length that might be correlated with myopia progression. Optical coherence tomography (OCT) provides a tool for imaging the choroid, however, with certain difficulties because of a limited visibility of the scleral-choroidal interface. Considering the previously reported effect sizes of thickness change in human myopia research, this study investigated the repeatability of automated 3D choroidal segmentation across the macular area of 6 × 6 mm. Fifteen subjects underwent nine volume scans in two OCT devices with analysis of the 95% interval of repeatability, intersubject and intrasubject variations, as well as interdevice agreement. Repeatability generally improved with increasing eccentricity from the fovea. The nasal perifoveal region exhibited the best repeatability with ±19 and ±21 μm in both OCT devices, whereas the subfovea showed a repeatability of ±57 and ±44 μm, respectively. High inter- and intrasubject variations were observed, together with a negative bias in the device agreement. Although there is still limited data on thickness changes of the nasal choroid, future studies could focus more on measuring the effect size in the nasal perifoveal area to account for metrological issues in choroidal segmentation.
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http://dx.doi.org/10.1038/s41598-019-56915-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6937308PMC
December 2019

Direct modeling of foveal pit morphology from distortion-corrected OCT images.

Biomed Opt Express 2019 Sep 26;10(9):4815-4824. Epub 2019 Aug 26.

Institute for Ophthalmic Research, Eberhard Karls University Tuebingen, Elfriede-Aulhorn-Str. 7, Tuebingen, 72076, Germany.

Inherent distortions affect the spatial geometry of optical coherence tomography (OCT) images and consequently the foveal pit dimensions. Distortion correction provides an accurate anatomical representation of the retinal shape. A novel approach that automatically extracts foveal pit metrics from distortion-corrected OCT images using a sum of Gaussian function is presented. Foveal width, depth and slope were determined in 292 eyes with low fitting errors and high repeatability. Comparisons to undistorted scans revealed significant differences. To conclude, the internal OCT distortions affect the measurements of the foveal pit with their correction providing further insights into the role of foveal morphology in retinal pathologies and refractive development.
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http://dx.doi.org/10.1364/BOE.10.004815DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6757460PMC
September 2019

The effect of the optical design of multifocal contact lenses on choroidal thickness.

PLoS One 2018 16;13(11):e0207637. Epub 2018 Nov 16.

Institute for Ophthalmic Research, Eberhard Karls University Tuebingen, Tuebingen, Germany.

Studies have found reduced myopia progression with multifocal contact lenses, albeit with an unclear mechanism behind their protective effect. It is hypothesized that the induced myopic defocus of the addition zones of the multifocal contact lenses leads to choroidal thickening and therefore inhibits eye growth. In the current study, the effect of the optical design of multifocal contact lenses on choroidal thickness was investigated. Eighteen myopic participants wore four different contact lenses ((1) single-vision lenses corrected for distance, (2) single-vision lenses with +2.50 D full-field defocus, (3) Multifocal center-distance design, (4) Multifocal center-near design, both with addition power +2.50 D) for 30 min each on their right eye. Automated analysis of the macular choroidal thickness and vitreous chamber depth were performed before and after the wear of each of the contact lenses. Peripheral refraction profiles in primary gaze were obtained using eccentric photorefraction prior to contact lens wear. Choroidal thickness and vitreous chamber depth showed no significant differences to baseline with any of the contact lenses (all p > 0.05). Choroidal thickness increased by +2.1 ± 11.1 μm with the Multifocal center-distance design, by +2.0 ± 11.1 μm with the full-field defocus lens, followed by the Multifocal center-near design with +1.6 ± 11.3 μm and the single-vision contact lens correcting for distance with +0.9 ± 11.2 μm. Multifocal contact lenses have no significant influence on choroidal thickness after short-term wear. Therefore, changes in choroidal thickness might not be the main contributor to the protective effect of multifocal contact lenses in myopia control.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0207637PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6239323PMC
April 2019