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Specular Microscopy (specular + microscopy)
Selected Abstracts4334: Fully automated corneal endothelial morphometry of a large set of images captured by clinical specular microscopyACTA OPHTHALMOLOGICA, Issue 2010C BUCHT Purpose The endothelial cell density is the most important morphological factor of the corneal endothelium. Morphometry of the corneal endothelium is an important part of several clinical applications. Morphometry of the endothelium is presently carried out by semi automated analysis of pictures captured by Clinical Specular Microscopy (CSM). The need of operator involvement makes this process time consuming. This study presents a method for fully automated analysis of a large range of in vivo images of the corneal endothelium, captured by CSM, using Fourier analysis. Methods Software was developed in the mathematical programming language MATLAB. Pictures of the corneal endothelium, captured by CSM, were read into the analysis software. The software performed automated digital enhancement of the images. The enhanced images were Fourier transformed, using the Fast Fourier Transform. Relevant characteristics of the Fourier transformed images were identified and sampled. The data obtained from each transformed image was used to calculate the mean cell density of the original image, which in turn was compared to a semi automated method cell density estimate. The calculation was based on well known diffraction theory. Results Estimated cell densities of the corneal endothelium were obtained, using fully automated analysis software on 292 images captured by CSM. Using linear regression, a relatively large correlation between the estimates of the fully automated method and the semi automated method was found. Conclusion The results using the considerably faster fully automated method are highly encouraging for further development and implementation of the method. [source] Central corneal thickness in European (white) individuals, especially children and the elderly, and assessment of its possible importance in clinical measures of intra-ocular pressureOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 6 2002Michael J. Doughty Purpose:,To ascertain the impact of central corneal thickness (CCT, as assessed by pachometry) and central corneal curvature (as assessed by keratometry) on clinical measures of intra-ocular pressure (IOP, as assessed by tonometry), especially in the young and elderly. Methods:,Pachometry, keratometry and tonometry were carried out on three groups, namely children aged 5,15 years, adults aged 32,60 years, and elderly individuals aged between 61 and 82 years. For children, ultrasound pachometry was combined with non-contact tonometry (NCT), specular microscopy was used with Perkins tonometry in the adults, and ultrasound pachometry was used with Perkins tonometry for the elderly. Central corneal curvature was assessed by keratometry. Results:,The average CCT in children was 0.529 ± 0.034 mm (n=104, ±S.D.), averaged 0.533 ± 0.033 in adults (n=75) and 0.527 ± 0.034 mm (n=91) in the elderly. Tonometry values averaged 16.7 ± 2.9 mm in children, 13.0 ± 3.5 mmHg in adults and 13.6 ± 2.5 mm in the elderly group. Central corneal thickness values were not predictably different in relation to central corneal curvature values. Regression analyses indicated that the tonometry values were higher in both children and the elderly who had thicker corneas (and vice versa) (p , 0.003), with the measures increasing by 1.3 ± 0.4 and 2.6 ± 0.4 mmHg for a 10% difference in CCT in children and the elderly, respectively. For adults, no statistically significant difference in tonometry values could be demonstrated with respect to CCT (<1 mmHg for a 10% difference in CCT), and for no group were the CCT or tonometry values predictably different in relation to central corneal curvature values. Conclusions:,The results of these studies, albeit relatively small scale, indicate that in young or elderly individuals with essentially normal IOP and CCT measures, the tonometry values show only small differences with respect to CCT. The slope in the observed relationship was not that different from an average of 1.5 mmHg for a 10% different in CCT, as obtained from a literature analysis over a 30-year period. The magnitude of the effect does not provide evidence that pachometry needs to be routinely performed in glaucoma screening protocols based on tonometry. Notwithstanding, the finding of higher than expected tonometry values should be further investigated, by pachometry, especially in very young children and in the elderly. [source] Clinical phenotype of posterior polymorphous corneal dystrophy in a family with a novel ZEB1 mutationACTA OPHTHALMOLOGICA, Issue 6 2010Dan Q. Nguyen Acta Ophthalmol. 2010: 88: 695,699 Abstract. Purpose:, To describe the clinical phenotype in a family with posterior polymorphous corneal dystrophy (PPCD) and a novel mutation in the ZEB1 gene. Methods:, Clinical examination, anterior segment photography, specular microscopy and electrophysiological investigations were performed and quantified. Genomic DNA extracted from peripheral blood was sequenced for ZEB1 exons. Cosegregation of identified mutation with the disease status in the family was confirmed using polymerase chain reaction and restriction fragment length polymorphism. Results:, Ocular examination was performed on five family members from two generations. Three had anomalies of the corneal endothelium that were consistent with PPCD. Endothelial cell counts ranged from 2306 to 2987 mm2 (ref. 2000,4000 cells/mm2). No evidence of glaucoma or retinal abnormalities was observed. Extraocular abnormalities such as inguinal herniation, hydrocoele and possible bony or connective tissue anomalies were part of the disease spectrum in this family. Mutation analysis revealed a novel change in exon 5 of ZEB1 (c.672delA) that cosegregated with the affected disease status. Conclusion:, The detailed clinical features of PPCD associated with a novel ZEB1 mutation are supportive of the previously proposed range of phenotype parameters. Further phenotype,genotype correlations may provide insights into the clinical variability and pathological processes affecting the corneal endothelium, Descemet's membrane, retinal photoreceptor function and extraocular tissues of some patients. [source] 4334: Fully automated corneal endothelial morphometry of a large set of images captured by clinical specular microscopyACTA OPHTHALMOLOGICA, Issue 2010C BUCHT Purpose The endothelial cell density is the most important morphological factor of the corneal endothelium. Morphometry of the corneal endothelium is an important part of several clinical applications. Morphometry of the endothelium is presently carried out by semi automated analysis of pictures captured by Clinical Specular Microscopy (CSM). The need of operator involvement makes this process time consuming. This study presents a method for fully automated analysis of a large range of in vivo images of the corneal endothelium, captured by CSM, using Fourier analysis. Methods Software was developed in the mathematical programming language MATLAB. Pictures of the corneal endothelium, captured by CSM, were read into the analysis software. The software performed automated digital enhancement of the images. The enhanced images were Fourier transformed, using the Fast Fourier Transform. Relevant characteristics of the Fourier transformed images were identified and sampled. The data obtained from each transformed image was used to calculate the mean cell density of the original image, which in turn was compared to a semi automated method cell density estimate. The calculation was based on well known diffraction theory. Results Estimated cell densities of the corneal endothelium were obtained, using fully automated analysis software on 292 images captured by CSM. Using linear regression, a relatively large correlation between the estimates of the fully automated method and the semi automated method was found. Conclusion The results using the considerably faster fully automated method are highly encouraging for further development and implementation of the method. [source] Effect on corneal endothelial cell count of traumatic microhyphaema and hyphaemaACTA OPHTHALMOLOGICA, Issue 5 2009Jeffrey Pong Abstract. Purpose:, This study investigates changes in the corneal endothelial count in patients after non-penetrating ocular trauma (NPOT) with associated microhyphaema or hyphaema. Methods:, A total of 48 patients were recruited and divided into grade 1 (microhyphaema) and grade 2 (hyphaema) injury groups. Both central and inferior corneal endothelial counts were measured with specular microscopy. Results:, Neither central nor inferior corneal endothelial counts on the injured eye showed significant decrease compared to the normal contralateral eye across the two injury groups. The mean cell count of the central cornea of the hyphaema group showed a drop of 1.9% compared to the normal controls. Conclusion:, The duration and severity of non-penetrating ocular trauma with microhyphaema or hyphaema did not appear to show a statistically significant loss in corneal endothelial cell count compared to the normal control. [source] | ||||||||||