Dataset Information

Assessment of corneal epithelial thickness mapping in epithelial basement membrane dystrophy.

ABSTRACT: PURPOSE:To investigate the corneal epithelial thickness topography with optical coherence tomography (OCT) and its relationship with vision quality in epithelial basement membrane dystrophy (EBMD). METHODS:45 eyes of EBMD patients, 26 eyes of dry eye (DED) patients and 22 eyes of normal subjects were enrolled. All participants were subjected to 9-mm corneal epithelial mapping with OCT and vision quality was assessed with the optical quality analysis system using the objective scatter index (OSI). Central, superior, inferior, minimum, maximum, and standard deviation of epithelium thickness (Irregularity), were analysed and correlations with the OSI were calculated. RESULTS:The mean (±SD) central, inferior and maximum epithelial thicknesses of the EBMD patients (respectively, 56.4 (±8.1) ?m, 58.9 (±6.4) ?m, and 67.1 (±8.3) ?m) were thicker compared to DED patients (P<0.05) and normal subjects (P<0.05). We found greater irregularity of epithelial thickness in EBMD (5.1±2.5 ?m) compared to DED patients (2.6±1.0 ?m) (P = 4.4.10-6) and normal subjects (2.1±0.7 ?m) (P = 7.6.10-7). The mean OSI was worse in EBMD patients than in DED patients (P = 0.01) and compared to normal subjects (P = 0.02). The OSI correlated with the epithelial thickness irregularity (Spearman coefficient = 0.54; P = 2.65.10-5). CONCLUSIONS:The OCT pachymetry map demonstrated that EBMD patients had thicker corneal epithelium in the central and inferior region. These changes were correlated with objective measurements of vision quality. This OCT characterisation of the EMBD provides a better understanding of the epithelial behaviour in this dystrophy and its role in vision quality.

SUBMITTER: Buffault J

PROVIDER: S-EPMC7688121 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

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Assessment of corneal epithelial thickness mapping in epithelial basement membrane dystrophy.

Buffault Juliette J Zéboulon Pierre P Liang Hong H Chiche Anthony A Luzu Jade J Robin Mathieu M Rabut Ghislaine G Labetoulle Marc M Labbé Antoine A Baudouin Christophe C

PloS one 20201125 11

<h4>Purpose</h4>To investigate the corneal epithelial thickness topography with optical coherence tomography (OCT) and its relationship with vision quality in epithelial basement membrane dystrophy (EBMD).<h4>Methods</h4>45 eyes of EBMD patients, 26 eyes of dry eye (DED) patients and 22 eyes of normal subjects were enrolled. All participants were subjected to 9-mm corneal epithelial mapping with OCT and vision quality was assessed with the optical quality analysis system using the objective scat ...[more]

PMID: 33237913

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Project description:ObjectiveTo map the corneal epithelial thickness with Fourier-domain optical coherence tomography (OCT) and to develop epithelial thickness-based variables for keratoconus detection.DesignCross-sectional observational study.ParticipantsOne hundred forty-five eyes from 76 normal subjects and 35 keratoconic eyes from 22 patients.MethodsA 26,000-Hz Fourier-domain OCT system with 5-?m axial resolution was used. The cornea was imaged with a Pachymetry + Cpwr scan pattern (6-mm scan diameter, 8 radials, 1024 axial-scans each, repeated 5 times) centered on the pupil. Three scans were obtained at a single visit in a prospective study. A computer algorithm was developed to map the corneal epithelial thickness automatically. Zonal epithelial thicknesses and 5 diagnostic variables, including minimum, superior-inferior (S-I), minimum-maximum (MIN-MAX), map standard deviation (MSD), and pattern standard deviation (PSD), were calculated. Repeatability of the measurements was assessed by the pooled standard deviation. The area under the receiver operating characteristic curve (AUC) was used to evaluate diagnostic accuracy.Main outcome measuresDescriptive statistics, repeatability, and AUC of the zonal epithelial thickness and diagnostic variables.ResultsThe central, superior, and inferior epithelial thickness averages were 52.3 ± 3.6 ?m, 49.6 ± 3.5 ?m, and 51.2 ± 3.4 ?m in normal eyes and 51.9 ± 5.3 ?m, 51.2 ± 4.2 ?m, and 49.1 ± 4.3 ?m in keratoconic eyes. Compared with normal eyes, keratoconic eyes had significantly lower inferior (P = 0.03) and minimum (P<0.0001) corneal epithelial thickness, greater S-I (P = 0.013), more negative MIN-MAX (P<0.0001), greater MSD (P<0.0001), and larger PSD (P<0.0001). The repeatability of the zonal average, minimum, S-I, and MIN-MAX epithelial thickness variables were between 0.7 and 1.9 ?m. The repeatability of MSD was better than 0.4 ?m. The repeatability of PSD was 0.02 or better. Among all epithelial thickness-based variables investigated, PSD provided the best diagnostic power (AUC = 1.00). Using an PSD cutoff value of 0.057 alone gave 100% specificity and 100% sensitivity.ConclusionsHigh-resolution Fourier-domain OCT mapped corneal epithelial thickness with good repeatability in both normal and keratoconic eyes. Keratoconus was characterized by apical epithelial thinning. The resulting deviation from the normal epithelial pattern could be detected with very high accuracy using the PSD variable.Financial disclosure(s)Proprietary or commercial disclosure may be found after the references.

Project description:PURPOSE: With advances in phenotyping tools and availability of molecular characterization, an increasing number of phenotypically and genotypically diverse inherited corneal dystrophies are described. We aimed to determine the underlying causative genetic mechanism in a three-generation pedigree affected with a unique anterior membrane corneal dystrophy characterized by early onset recurrent corneal erosions, small discrete focal opacities at the level of Bowman layer and anterior stroma, anterior stromal flecks, and prominent corneal nerves. METHODS: Twenty affected and unaffected members of a three-generation family were examined and extensively clinically characterized including corneal topography and in vivo confocal microscopy, and biological specimens were collected for DNA extraction. Mutational analysis of two corneal genes (TGFBI [Transforming Growth factor-beta induced] and ZEB1 [zinc finger E box-binding homeobox 1]) was undertaken, in addition to testing with the Asper Corneal Dystrophy gene chip (Asper Ophthalmics, Tartu, Estonia). Subsequent Genotyping To 11 Known Corneal Gene Loci (COL8A2 [Collagen, Type VIII, Alpha-2], TACSTD2 [Tumor-Associated Calcium Signal Transducer 2], PIP5K3 [Phosphatidylinositol-3-Phosphate 5-Kinase, Type III], GSN [Gelsolin], KERA [Keratocan], VSX1 [Visual System Homeobox Gene 1], COL6A1 [Collagen, Type VI, Alpha-1], MMP9 [Matrix Metalloproteinase 9], KRT3 [Keratin 3]), and two putative loci, 3p14-q13 and 15q22.33-24) was undertaken using polymorphic markers, and haplotypes constructed. Multipoint linkage analysis was performed to generate LOD scores and produce LOD plots across the candidate intervals. RESULTS: No pathogenic sequence variations were detected in TGFBI or ZEB1 of the proband nor on the Asper Corneal Dystrophy gene chip (302 mutations in 12 genes). Multipoint linkage analysis of 11 known corneal genes and loci generated negative LOD plots and was able to exclude all genes tested including PIP5K3. CONCLUSIONS: Exclusion of linkage to candidate corneal loci combined with an absence of pathogenic mutations in known corneal genes in this pedigree suggest a different genetic causative mechanism in this dystrophy than the previously documented corneal genes. This unique phenotype of an anterior membrane dystrophy may therefore provide an opportunity to identify a new gene responsible for corneal disease.

Project description:Purpose To develop a model to predict corneal improvement after Descemet membrane endothelial keratoplasty (DMEK) for Fuchs endothelial corneal dystrophy (FECD) from Scheimpflug tomography. Design Cross-sectional study. Participants Forty-eight eyes (derivation group) and 45 eyes (validation group) with a range of severity of FECD undergoing DMEK. Methods Scheimpflug images were obtained before and after DMEK. Before DMEK, pachymetry map and posterior elevation map patterns were quantified by a special image analysis program measuring tomographic features of edema (loss of regular isopachs, displacement of the thinnest point of the cornea, posterior surface depression). Image-derived novel parameters were combined with instrument-derived parameters, and the relative influences of parameters associated with the change in central corneal thickness (CCT) after DMEK in the derivation group were determined by using a gradient boosting machine learning model. The parameters with highest relative influence were then fit in a linear regression model. The derived model was applied to the validation group. Correlations and agreement were assessed between predicted and observed changes in CCT. Main Outcome Measures Predictive power (R2) and mean difference between predicted and observed change in CCT. Results The gradient boosting machine model identified 4 novel parameters of isopach circularity and eccentricity and 1 instrument-derived parameter (posterior surface radius); preoperative CCT was a poor predictor. In the derivation group, the model strongly predicted the change in CCT after DMEK (R2 = 0.80; 95% confidence interval [CI], 0.71–0.89) and the mean difference between predicted and observed change was, by definition, 0 μm. When the same 5 parameters were fit to the validation group, the model performed very highly (R2 = 0.89; 95% CI, 0.84–0.94). When the coefficient estimates from the derivation model were used to predict the change in CCT in the validation group, the predictive power was also high (R2 = 0.78; 95% CI, 0.68–0.88), and the mean difference was 4 μm (predicted minus observed). Conclusions Scheimpflug tomography maps of corneas with FECD can predict the improvement in CCT after DMEK, independent of preoperative corneal thickness measurement. The model could be applied in clinical practice or for clinical research of FECD.

Dataset Information

Assessment of corneal epithelial thickness mapping in epithelial basement membrane dystrophy.

Publications

Assessment of corneal epithelial thickness mapping in epithelial basement membrane dystrophy.

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