precaution while using microscope

The design of a microscope will often times (partially) excuse incorrect treatment. However, the front nosecone of the objective with the sensitive front lens element is one particularly critical area. A number of precautions should be taken to ensure the objective lens is not damaged. The entire front optics of objectives with a high magnification are (in most cases) contained in a resilient, spring loaded mount. When touched, this mount backs away slightly (Figure 4). However, the distance available for this movement is very small (approximately 2 3 millimeters). Therefore, make sure that you do not move the stage too far upwards while focusing. In such cases, the sample will press against the objective tip, and once the front lens cannot retreat any further, the outcome may be an expensive breakage of glass. Immersion objectives have an additional protection facility to the one described above. Some varieties can be locked in the topmost position by carefully turning the front lens group housing (nosecone). The objectives can thus be parked at a safe distance. On the other hand, the escape route described above is then no longer available, and if one tries to use the objective in this retracted mode, the image will be distorted and there will be the danger of the stage colliding with other objectives when the nosepiece turret is rotated.

The human body can endure stationary positions for extended periods if it is in a neutral body posture a position that can be maintained without a concerted effort or contortions. A neutral body posture is essential to working efficiently and effectively at the microscope for long hours. Because not everyone is able to buy a new, ergonomically designed microscope or workstation, the smartest idea is to find the means to modify the microscope to fit the user rather than forcing the user into awkward positions.

Work/rest schedules should be appropriate. It is important to take breaks away from the microscope to counteract the build up of postural and visual fatigue. A well designed job will incorporate both microscope and non microscope tasks. Frequent short breaks are preferable to occasional long breaks. This enables relief from the static, maintained working posture and a chance to look around and vary the accommodation of the eyes. Computer users are recommended to take 5 minutes every hour away from the computer; it may be preferable to take half hourly breaks away from the microscope.

Visual strain is pronounced for operators with uncorrected astigmatism and fusion insufficiency (poor eye co ordination). It is important to treat these problems, see an optician. Scanning probe microscopy involves the interaction of a scanning probe with the surface of the object of interest. The development of microscopy revolutionized biology and remains an essential technique in the life and physical sciences.

Eye fatigue is minimised in a well designed visual environment. Where possible, avoid high light levels and high contrast in the microscope in comparison to the room surroundings. Minimise glare and reflections in the work area. Glare can be reduced by removing light sources from the visual field. This can be done by re positioning workstations, using blinds or curtains, removing highly reflective surfaces or by using shielding screens. The Health & Safety (Display Screen Equipment) Regulations 1992 give further information regarding work with VDU screens.

Sedentary workers are particularly susceptible to the effects of their work environment. Draughts, temperature extremes, poor air quality, inadequate lighting and noise affect comfort and performance. It is important to consider the needs and preferences of the individual.

Microscopists know how to align their microscope but few align themselves! Many users are slumpers and need training to avoid problems later. Optical or light microscopy involves passing visible light transmitted through or reflected from the sample through a single or multiple lensesto allow a magnified view of the sample.The resulting image can be detected directly by the eye, imaged on a photographic plate orcaptured digitally. The single lens with its attachments, or the system of lenses and imaging equipment, along with the appropriate lighting equipment, sample stage and support, makes up the basic light microscope. The most recent development is the digital microscope, which uses a CCD camera to focus on the exhibit of interest. The image is shown on a computer screen, so eye pieces are unnecessary.

The bench height is important and ideally it should be adjustable so that eye piece height is adjustable but this is often not practicable due to cost. What follows will be based on a fixed bench height. Microscopy requires a good seating position in an adjustable, ergonomically designed chair. The back should be high enough to support the shoulder blades and be adjustable for height and angle, with the most prominent part being the lumbar support. The seat should be low enough to have the back perfectly straight to see through the oculars. Then move the chair towards the bench so that the chair fully supports the back this feels unnatural at first. Most people have the seat too high, which results in hunching. Sitting for long periods places strain on the lower back.

The microscopes used in this lab arecompound lightmicroscopes. They are designed to beparfocal; that is, if the microscope is clearly focused on a specimen with a lower power objective, it will be clearly focused (or very nearly so) when you swing the next highest objective into place.

Position the microscope so that you can comfortably look through the ocular. Adjust your chair height if necessary. See that the microscope is plugged into the outlet properly, with very little slack in the cord. Make sure the scanning (4X) power objective is in operating position. The scanning power objective lens magnifies the image by a factor of 4, for a total of 40X. (Total magnificationis the product of the magnifications of each lens being used, that is, the ocular lens at 10X and, in this case, the scanning lens at 4X.) Use of the e slide demonstrates the upside down, reversed image: as you move the slide to the left, the image goes to the right; as you move the slide away from you, the image moves toward you. Also with the e slide you can learn to appreciate the concept offield of view, which lessens as you advance to higher magnifications.