Biomaterial Database

Optical principles for estimation of endothelial cell density with the non-contact specular microscope. 1979

T Olsen

In non-contact specular microscopy of corneal endothelium, endothelial cell density is overestimated due to the angle of observation and the curvature of cornea. On the basis of theoretical considerations, it is concluded that if the angle of observation is kept at a small value the curvature of cornea contributes only insignificantly to this overestimation, the major determinant being the angle of observation. When an angle of 46 degrees is chosen between slit illumination and optical axis of the microscope it is calculated that estimates of endothelial cells should be multiplied with a factor of 0.959 to correct for the angle effect. Six eye were photographed with both a contact and non-contact specular microscope and endothelial cell density estimated. Mean observed difference in cell counts was +5.5% without correction and +1.2% with correction for angle effect. 95% confidence limits for the difference with correction were -3.7 and +6.0% respectively showing that estimates of endothelial cell density obtained with the non-contact specular microscope agree closely with those obtained by contact specular microscopy when corrected for angle of observation.

UI	MeSH Term	Description	Entries
D008853	Microscopy	The use of instrumentation and techniques for visualizing material and details that cannot be seen by the unaided eye. It is usually done by enlarging images, transmitted by light or electron beams, with optical or magnetic lenses that magnify the entire image field. With scanning microscopy, images are generated by collecting output from the specimen in a point-by-point fashion, on a magnified scale, as it is scanned by a narrow beam of light or electrons, a laser, a conductive probe, or a topographical probe.	Compound Microscopy,Hand-Held Microscopy,Light Microscopy,Optical Microscopy,Simple Microscopy,Hand Held Microscopy,Microscopy, Compound,Microscopy, Hand-Held,Microscopy, Light,Microscopy, Optical,Microscopy, Simple
D002452	Cell Count	The number of CELLS of a specific kind, usually measured per unit volume or area of sample.	Cell Density,Cell Number,Cell Counts,Cell Densities,Cell Numbers,Count, Cell,Counts, Cell,Densities, Cell,Density, Cell,Number, Cell,Numbers, Cell
D003315	Cornea	The transparent anterior portion of the fibrous coat of the eye consisting of five layers: stratified squamous CORNEAL EPITHELIUM; BOWMAN MEMBRANE; CORNEAL STROMA; DESCEMET MEMBRANE; and mesenchymal CORNEAL ENDOTHELIUM. It serves as the first refracting medium of the eye. It is structurally continuous with the SCLERA, avascular, receiving its nourishment by permeation through spaces between the lamellae, and is innervated by the ophthalmic division of the TRIGEMINAL NERVE via the ciliary nerves and those of the surrounding conjunctiva which together form plexuses. (Cline et al., Dictionary of Visual Science, 4th ed)	Corneas
D004727	Endothelium	A layer of epithelium that lines the heart, blood vessels (ENDOTHELIUM, VASCULAR), lymph vessels (ENDOTHELIUM, LYMPHATIC), and the serous cavities of the body.	Endotheliums
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man