Posture and microscope adjustment
Introduction
Adjustments to sitting position and the microscope go hand in hand. Whereas in a clinical setting there may be practical limitations on how one can sit and mount the microscope, this tutorial offers scope to learn how to reduce potential discomfort wherever possible. The first step in setting up your workspace should be to assume a physiologically optimal sitting position. Sitting comfortably, without using too much muscle tone to maintain posture, is important in keeping physical exhaustion, tremor and pain to a minimum. Once we have explained what an ergonomic sitting position is, we will demonstrate adjustment of the microscope using a standard laboratory microscope. You may find that the specifics of adjusting your own microscope vary, but the general principles should apply.
Posture and Microscope Adjustment
To begin with, place your feet in front of your chair, approximately shoulderwidth apart. In this position you have three points of balance, providing a maximum of stability and symmetrical muscle tone across your legs and back. Set the height of your chair so that your hip joints are situated at least as high as your knee joints. This tilts your pelvis forward so that you can maintain a natural and ergonomically correct spine position over a longer period with ease. To straighten out your spine and support it with your abdominal muscles, draw your navel inwards towards your spine. Rest your forearms on the table to prevent tiring of your arm and shoulder muscles, leading to large amplitude tremor. Place your hands on the work surface to reduce small amplitude tremor. To achieve an ergonomically correct cervical spine position, push your head upwards to straighten your neck and slightly tilt your chin downwards, as if you were looking down to the ground in the distance. The entire microscope should be mounted to match the sitting position. The eyepieces should be at the correct distance to the operator and at the correct height to meet the eyes. In order to be able to sit straight while still obtaining a sharp image, or if you find you are straining your wrists because they are too low in relation to the workspace, you may need to raise your workspace. To stay comfortable you can role up some towels and place them under your wrists. If you are using your visual aid (eyeglasses/contact lenses), or have no eyesight impairment, set the eyepieces to 0 (zero) diopters. If you have a visual aid, but prefer to work without it, most eyepieces can be set to correct simple myopia, or hypermetropia according to your prescription. Turn on the light source. To keep potentially significant eyestrain to a minimum, use ambient light and keep looking through the microscope with as little interruption as possible, so your eyes do not have to repeatedly adjust to different degrees of brightness. Now set your interpupillary distance. You should obtain one single circular visual field that does not float in front of your eyes. If you experience difficulty in obtaining such a visual field, make sure that the distance between your eyes and the eyepieces is neither too long, nor too short. To keep this distance, you may want to use the shades available on some eyepieces. In order to set the focus in the plane you want to work in, initially set the microscope to its minimal magnification. Adjust the focus using a fine object that provides a good contrast, such as the tips of a microsurgical instrument. Once you have obtained a sharp image, switch to maximal magnification. Proceed with the fine adjustment of the focus. As long as you keep working in the same plane, you can now switch between different degrees of magnification without readjusting the focus. If you enter a different operating plane, you will need to readjust the focus. If you cannot obtain a sharp image at either minimal or maximal magnification, you may have to alter the distance between microscope and work field. When you take a break, turn off the light source to prolong the lifetime of the light bulb and reduce energy expense.