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Reflection contrast was developed by the Ernst Leitz Wetzlar Company in the seventies. It presents a microscopic technique which realizes optimal contrast on visualizing cell structures by means of reflected light.When transparent specimens are examined in thin-layer preparations typical interference patterns occur in reflection contrast. Thus, erythrocytes show characteristic annular shaped interference lines consisting of alternating maxima and minima. The bright maxima and dark minima mark cell regions of constant thickness in a manner similar to cartographic altitude lines or isohypses. When the examinations are carried out in monochromatic green light, the difference in thickness between maximum and adjacent minimum lines is about 113 nm. Based on this, differences in local thickness are measurable. With the help of drawing modes used in cartography, three dimensional reconstructions of cell reliefs can be carried out. The interference lines differ in their position when specimens are illuminated in monochrome light with different (long and short) wave lengths. In this case, the absolute local thickness of transparent cells can be calculated by specific interferometric formulas. When the path of the illuminating light beam is appropriately modified, the three dimensional reliefs of cells are also visible in life microscopy. The resulting three dimensional images are similar to interference contrast or scanning electron microscopy. It can be taken into account, as advantages of reflection contrast, that this method can be combined with all examination modes based on transmitted light (bright- and darkfield, phase and interference contrast, flourescence microscopy), suitable for examinations of living specimens, too. The measurements and three dimensional reconstructions mentioned above were carried out with normal erythrocytes and several pathological erythrocytes from patients affected with hereditary spherocytosis, sickle cell anemia and thalassemia. All methods for experimental cytometric measurements were elaborated in cooperation with the Institute for Anatomy, University of Bonn, section for light microscopy (head: Prof. Dr. Franz Pera) in 1978-1982. The methods were carried out in clinical practice combined with systems for automatical image analyses in cooperation with the section for angiology, University of Bonn (head: Prof. Dr. Truebestein), based on cases with occlusive arterial disease, pernicious anemia and Raynaud's syndrome.
Erythrocyte in a stained blood smear, reflection contrast, Stained erythrocytes in modified reflection contrast Three dimensional reconstructions of normocytes and pathological erythrocytes,
Publications: Pera, F., Piper, J.: Quantitative morphological analyses of erythrocytes by reflection contrast microscopy. Piper, J., Pera, F.: Reconstructions of the surface reliefs of erythrocytes with help of the Leitz equipment for reflection contrast.microscopy (in German) Pera, F., Piper, J., Kunde, V.: Morphometrc examinations of blood cell alterations induced by preparations in smears Wilgalis, M., Pera, F., Trübestein, G., Ludwig, M., Piper, J.: Piper, J.: Qualitative and quantitative morphological analyses of normal and pathological erythrocytes by reflection contrast microscopy (dissertation, in German), 1983
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