Eyepiece Health Dictionary

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Eyepiece: From 1 Different Sources

n. the lens or system of lenses of an optical instrument, such as a microscope, that is nearest to the eye of the examiner. It usually produces a magnified image of the previous image formed by the instrument. Compare objective.
Health Source: Oxford | Concise Colour Medical Dictionary
Author: Jonathan Law, Elizabeth Martin

Microscope

An instrument for producing a magnified image of a small object. Microscopes are used to examine the structure and chemical composition of cells and tissues, and to investigate microorganisms and diseased tissues. In the operating theatre, microscopes are used in microsurgery.

Compound microscopes are the most widely used type. They have 2 lens systems (the objective and the eyepiece), mounted at opposite ends of a tube called the body tube. There is a stage to hold the specimen, a light source, and an optical condenser which concentrates the light. The maximum magnification is about 1,500 times.

Phase-contrast and interference microscopes are modified light microscopes that allow unstained transparent specimens to be seen. They are used for examining living cells and tissues.

Fluorescence microscopes use ultraviolet light to study specimens stained with fluorescent dyes.Electron microscopes give much higher magnifications than light microscopes by using a beam of electrons instead of light. There are 2 types: transmission electron microscopes (TEMs) and scanning electron microscopes (SEMs). TEMs can magnify up to about 5,000,000 times, enabling tiny viruses and molecules to be seen. SEMs have a lower maximum magnification (100,000 times), but produce 3-dimensional images. This makes them useful for studying surface structures of cells and tissues.... microscope

Laparoscope

An instrument consisting, essentially, of a rigid or ?exible cylinder, an eyepiece and a light source, which is inserted through a small incision into the abdominal cavity (which has already been distended with carbon dioxode gas). The laparoscope allows the contents of the abdominal cavity to be examined without performing a LAPAROTOMY. Some operations may be performed using the laparoscope to guide the manipulation of instruments inserted through another small incision – for example, STERILISATION; CHOLECYSTECTOMY. (See also ENDOSCOPE; MINIMALLY INVASIVE SURGERY (MIS).)... laparoscope

Endoscope

A tube-like viewing instrument that is inserted into a body cavity to investigate or treat disorders. Endoscopes can be either flexible or rigid, depending on the part of the body to be examined. A flexible fibre-optic endoscope is a bundle of light-transmitting fibres. At the head, it has an eyepiece, steering device, and power source; at the tip, there is a light, a lens, an outlet for air or water, and sometimes a camera that transmits a picture to a screen. Side channels enable various surgical instruments to be passed down the endoscope. A rigid endoscope is a straight tube with a light attached.... endoscope

Ocular

Relating to or affecting the eye and its structures; also the eyepiece of an optical device, such as a microscope.... ocular

Achromatic Lenses

lenses that are specially designed to give clear images, eliminating the coloured fringes that are produced with ordinary lenses (caused by splitting of the light into different wavelengths and hence its component colours). Such lenses are useful in scientific instruments, such as the eyepieces of microscopes.... achromatic lenses

Objective

n. (in microscopy) the lens or system of lenses in a light microscope that is nearest to the object under examination and furthest from the *eyepiece. In many types of microscope interchangeable objectives with different powers of magnification are provided.... objective

Operating Microscope

a binocular microscope commonly in use for microsurgery. The field of operation is illuminated through the objective lens by a light source within the microscope (see illustration). Many models incorporate a beam splitter and a second set of eyepieces, to enable the surgeon’s assistant to view the operation.... operating microscope

Ultramicroscope

n. a microscope for examining particles suspended in a gas or liquid under intense illumination from one side. Light is scattered or reflected from the particles, which can be seen through the eyepiece as bright objects against a dark background.... ultramicroscope

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