what is diopter adjustment in microscope

Diopter adjustment is a feature in microscopes that allows the user to adjust the focus of one eyepiece to compensate for the difference in vision between their two eyes. This adjustment is necessary because sometimes our eyes are not both exactly the same as far as what you might call your glasses prescription might go. The diopter adjustment is usually located on one or both of the eyepiece tubes and can be adjusted by turning a knob or rotating the eye lenses. The adjustment should be made to each of the eyepieces individually. To correctly adjust the diopter on a lens, the user should first close one eye over the eyepiece with the diopter adjustment and normally focus the microscope so that the open eye sees the image in focus. Then, the user should adjust the diopter to align the two images into one by moving the two eyepiece stalks inwards/outwards. The diopter adjustment is different from the interpupillary adjustment, which is an adjustment for the distance between the viewers eyes.