Lamp, Slit, Illumination
Monday, September 11, 2006
Slit Lamp Illuminator produces an intensity of approximately 200 mW/cm2. Using halogen lamps, a higher luminance and color temperature can be obtained than with incandescent lamps. A high color temperature produces a greater amount of desired blue light. Many ocular structures are viewed through light scattering, and shorter wavelengths are scattered most. A light source with a high blue component will produce better structural illumination. In the slit lamp the light is focused at the slit aperture. A condensing lens focuses the light within the slit to the patient’s eye.
A number of design features allow the slit lamp to perform the following:
• Scattered light from adjacent tissue is reduced as the slit beam is narrowed, providing greater detail of the section under examination.
• Light coming in from the side provides stronger highlights and shadows and therefore texture showing elevations and depressions.
• A combination of a narrow beam and a dark pupillary background eliminates any extraneous light that could reduce contrast.
• Setting the angle of observation equal to the angle of illumination allows the structure of the front surface and the rear surface of the cornea to be observed.
• Using a wide beam directed to an area adjacent to the area of interest and a dark background allows backscattered light from a lesion to provide a higher contrast. This allows the borders of the lesion to be observed more accurately.
• Light can be sent through the pupil to the fundus and is reflected back providing an orange background. Holes in the iris or wrinkles in the cornea are silhouetted and easier to observe.
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Industrial Products
posted by JD52 @ 7:32 PM,
