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E. Scharfenberg, C. Foja, P. Wiedemann; Lens Densitometry and Thickness Measurements with the Oculus Pentacam . Invest. Ophthalmol. Vis. Sci. 2006;47(13):3295.
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The Oculus Pentacam, a rotating Scheimpflug camera that generates three dimensional images of the anterior segment, is acclaimed for its broad spectrum of computed measurements and features, high reproducibility, non–contact approach, speed and ease of usage, and has won acceptance particularly in examinations surrounding refractive surgery. The advantages and limitations of the densitometry feature of the Oculus Pentacam in a clinical setting were the primary focus of our investigation.
Anterior chamber images of over 200 live human eyes in mydriasis were generated using the Oculus Pentacam. Lens thickness, opacity, and measurement reproducibility were examined.
Position and extent of lens opacities were displayed and measurable in images made with both the 3D–scan and Enhanced Dynamic settings. Densitometry values are displayed per sagital plane as a relative quantity based on light scattering; a single densitometry value for the complete lens is not provided. In images determined by the Pentacam as having high examination quality (QS), central lens thickness measurements, as well as central anterior chamber depth, measured with the 3D scan setting (25 images per scan) with automatic initiation showed an intraindividual repeatability coefficient of 0.159 and 0.055, respectively.
The limitations of the Oculus Pentacam are partially inherent to the optically based Scheimpflug principle. Due to the scattering of light, the resolution of the densitometry function and, ultimately the computed opacity value, is subject to influence by the clarity of the cornea and anterior chamber, as well as opacities located predominantly in the anterior lens. Because of these influential factors, the Pentacam seems best implemented in serial or longitudinal studies of single individuals with regard to cataract development as opposed to interindividual comparisons.
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