Use of Light Microscope

• Light microscopy involves the use of optical lenses and light to magnify small samples and observe details not visible to the naked eye.

• A typical light microscope consists of an eyepiece (ocular lens), objective lenses, coarse and fine adjustment knobs, a stage for holding the slide, a condenser, an illuminator (usually a light source), and a diaphragm or iris to manage the amount of light reaching the sample.

• Specimens for light microscopy often need to be stained or dyed to enhance contrast and visibility, as many cells and their components are almost transparent.

• Light microscopes have a high power of resolution which allows individual cells and some of their larger internal structure to be seen.

• The use of a light microscope is the basic tool for many investigations in the health sciences - such as identifying abnormal cells in a biopsy, studying the structure of tissue, or observing the behavior of cultured cells.

• Binocular light microscopes (with two eyepieces) are commonly used because they offer three-dimensional viewing of the specimen.

• The magnifying power of a light microscope can be calculated by multiplying the power of the eyepiece lens by the power of the objective lens.

• The Limit of Resolution (the smallest detail that can be seen) of a light microscope is approximately 0.2 micrometers. This is determined by the diffraction limit, the fundamental limit of optical systems.

• There are limitations to using a light microscope; for example, smaller structures within the cell such as ribosomes, endoplasmic reticulum and ultra-structures like mitochondria cannot be clearly seen or distinguished because they are smaller than the limit of resolution.

• The process of preparing specimens for light microscopy can introduce distortions, alterations, or artifacts. Therefore, the interpretation of results requires awareness and understanding of these potential issues.

• Familiarity with the different parts of the microscope and their functions, as well as the appropriate methods and techniques for preparing and observing specimens, is crucial to the effective use of a light microscope in health science.