Microscope Use

To meet the high standards required in microscopy, it is essential to know the proper handling and manipulation of a microscope, its limitations, and the ways to keep it in good working condition. It is the responsibility of the immediate supervisor to ensure that the microscopists are conversant with the operations of the instrument and can follow the standard operating procedures as well as the manufacturer’s instructions in operating, maintaining and storing the microscope for day-to-day use.

a. Parts of the Microscope

b. Care and Maintenance of Microscope

Microscopes are to provide precise results. However, they are sensitive to pressure, movement, temperature, dust, etc. Care and maintenance must always be observed to ensure their effective and efficient use.

     b.1 Requirements for Microscope Use and Preventive Maintenance

The following materials, reagents, and equipment are the minimum requirements for using and maintaining the microscope:

i. Lens Paper 

ii. 70% alcohol (ethyl/isopropyl) 

iii. Aspirator Bulb / Rubber Bulb 

iv. Camel Hair Brush / Soft Make-Up Brush 

v. All-purpose wax/weather wax (not floor wax) 

vi. Soft lint- free cloth (muslin cloth or “pranela”) 

vii. Applicator Stick 

viii. Spare Bulb 

ix. other alternative light source (for areas without electricity) 

x. Equipment Maintenance Record (logbook) Polyvinyl Plastic Cover

     b.2 Cleaning the Microscope by Parts

Optical Parts:

Dry Objectives 

• Blow off dust particles using the rubber bulb and wipe the lens with a lens paper, moving the lens paper across and not circularly. 

Oil Immersion Objectives 

•  Remove oil with lens paper moistened with 70% alcohol if needed, moving the lens paper across and not circularly. 

Eyepiece / Ocular 

• Clean upper lens with a lens paper swab slightly moistened with 70% alcohol then followed by dry tissue swab (see Fig. 3) 

• Wipe in circular motion starting at the center going outward.

Figure 3: Preparation of Lens Paper Swab

Illumination Parts:

The condenser and mirror 

• Clean the same way as the objectives using soft cloth or lens paper 

The support and stage 

• Clean using soft cloth

     

     b.3. Handling and Usage

i. Avoid subjecting the microscope to sudden or severe impact as it is a precision instrument; 

ii. Do not use the microscope where it is subjected to direct sunlight, high temperature and humidity, dust or vibrations; 

iii. When moving the microscope, carry it with one hand under the base and the other hand holding the arm; 

iv. Do not hold the microscope by the stage, stage feed knobs, and observation tube to prevent damage; 

v. Do not move the microscope by sliding it on the table. Otherwise, the rubber feet might be damaged or peeled off; 

vi. Install the microscope on a flat sturdy surface. Never block the air vents on the underside of the base (e.g. placing microscope on a flexible surface such as carpet; 

vii. Cover the microscope when not in use with polyvinyl plastic cover; 

viii. Never leave the microscope without the eyepiece; 

ix. Line up the X 10 objective with the ocular when microscope is not in use; 

x. Never try to dismantle or clean any part of the microscope that is difficult to reach unless you have been trained to do so; 

xi. Clean oil immersion objective after use. Never use ordinary paper or cotton wool to clean the lenses of the microscope. Never use xylene in cleaning any part of the microscope; 

xii. Never touch the bulb and the lenses with bare fingers; xiii. Never exchange parts from one microscope to another. Even some models by the same manufacturer have different specifications.

     b.4 Storage

Fungus cannot grow on glass surfaces when the atmosphere is dry. In these circumstances, it is important to store microscope under dry conditions when not in use. Any of the following methods can be used:

Method 1. Keep the microscope in a warm cabinet with a tightly fitting door and two 25 watt bulbs constantly lighted inside. Depending on the size of the cabinet, you can add more 25 watt bulbs as long as the temperature inside the cabinet is kept constant at 30-35° C but with low humidity. 

Method 2. Keep all lenses and prism heads in an airtight box or dessicator where the air is kept dry by an active silica gel. 

A silica gel is a dessicant that has the ability to absorb water vapor from the air. Self-indicating silica gel is blue when active and turns pink as it absorbs water vapor. When silica gel turns bright pink, it can then be reactivated by heating. After cooling (when it becomes bright blue), it can be used again. 

Method 3. Keep the microscope in a continuously air-conditioned room. However, storing microscope in rooms with air-condition only during the working day are not suitable.

     b.5 Transporting the microscope

It is important that the microscope and its parts are properly secured inside its storage box when the microscope is to be transported from one location to another.

i. Loosen the observation tube clamping knob slightly, rotate the tube by 180o, and tighten the knob; 

ii. Put the transport band; 

iii. Secure the stage and other movable parts; Use various protective materials such as packaging carton, styrofoam or pad inside the storage box.

c. Safety Rules in Using the Microscope

It is important that safety precautions be observed while using the microscope to prevent harm to the microscopists and the facility.

(i) Never work with wet hands, wet body or clothes wet; 

(ii) Do not presume that the circuit is turned off; 

(iii) Do not remove equipment grounds; 

(iv) Do not use defective plugs and cords; 

(v) Always use the correct replacement parts; 

(vi) If the bulb burns out during observation, be certain to cool the defective 

bulb completely before replacement; 

(vii) Keep out of children’s reach especially for the BMMCs.

d. Inspection and Performance Check

This part deals with the routine inspections and performance checks before the unit is put to use and/or being kept after using. A regular and thorough inspection of the microscope will certainly help maintain good operational results and increase its technical lifespan. A weekly inspection of a microscope should include the following points:

i. Ensure that the following parts are clean: 

· all outer surfaces of the instrument - must be free of corrosion or other visible damage; 

· electrical plugs, sockets, cables 

· bulb 

ii. Keep the mounting shoulders of the objectives and the corresponding surfaces on the nosepiece absolutely clean. Otherwise, you will lose the proper positioning of the objectives regarding centering and focus. Be careful not to allow any dust or dirt to get into the objective during cleaning; 

iii. Tighten screws securely; 

iv. Check the that the following are functioning well: 

· the field stop diaphragm move through its full range of opening smoothly and easily 

· all blades of the iris must move properly; 

· the condenser height adjustment knob run smoothly through its full range. Some types have an adjustable brake while others are permanently set; 

· condenser centering screws must move the condenser smoothly and in all directions through its full range; 

· mechanical stage must move the specimen smoothly and without any play through its full range of adjustment in both directions. Check by observing at the microscope’s highest magnification; 

· the slightest touch of the control knob must result in a corresponding movement of the specimen. Keep in mind that one micron of stage movement observed at a magnification of 1000x looks like 1 mm viewed without a microscope and at a distance of 250 mm. Therefore, any disassembly, adjustment, re-greasing, etc. of mechanical stages should be performed only by a trained technician; 

· The nosepiece must rotate smoothly through 360˚, reaching all click-stop positions properly from either side and without any play. Any disassembly at this position interferes with the optical alignment and requires special alignment aids for readjustment; 

v. The fine and coarse focusing knobs must run smoothly through their full range of adjustment. Some types have an adjustable brake (see user’s manual), whereas others are permanently adjusted. Ensure specially that the stage does not lower itself automatically. Do not tighten the brake too much; 

vi. Ensure that the upper surface of the stand and the corresponding mounting surface of the observation tube is clean and free of corrosion. The fastening screw for the tube must hold it securely in place; 

vii. Adjustment of the interpupillary distance of the tube must run smoothly and without exerting undue force; 

viii. All optical surfaces must be absolutely clean. Pay special attention to: light bulb, cover glass on field stop, condenser front lens, objective front lens, upper surface of eye lens; 

ix. Consider the following options in the repair of the microscope. 

· Let user of microscope to attend training on preventive maintenance; 

· Send the microscope for repair to the health maintenance department of the provincial/regional hospitals with personnel trained on preventive maintenance; 

· Send microscope for repair to the DOH-national Health Maintenance Service (HMS) 

· Request CHD or HMS trained staff for repair assistance but provide travel allowance of staff as their counterpart) 

Source: Module on Preventive Maintenance, Care and Basic Troubleshooting on Clinical Laboratory Microscope (Hospital Maintenance Service, Davao)

e. Equipment Maintenance Record

It is important that the history of repair and maintenance of the microscope be documented and properly filed. The Equipment Maintenance Record shall have the following information.

(i) Name of equipment 

(ii) Manufacturer’s name, serial number or other unique identification 

(iii) Origin(from what institution) 

(iv) Date received 

(v) Date placed in service 

(vi) Condition when received (new, used) 

(vii) Details of maintenance carried out 

(viii) Current location, where appropriate 

(ix) Copy of manufacturer’s operating instructions, where available 

(x) History of damage, malfunction or repair (date repaired) 

(xi) Name and signature of technician

Source:  Department of Health - Malaria Control Program Manual of Procedures, Guidelines in the Diagnosis and Treatment of Malaria