Visual acuteness: The first step is to record visual acuity. Patients who require remedial lenses should wear them during trying. Visual acuity in each eye is tested as the opposite eye is covered.

The set of the microscope closest to the eye is the eyepiece or ocular based from Latin oculus, eye, as in oculist. The objective of a simple microscope magnifies the object and sends the enlarged image up the tube to where the ocular picks it up and magnifies it again. There are microscopes, and devices on more ordinary usages such as measuring the length of such an incredibly tiny cell as a bacterium.

The photographer has the option to use a standard lens mount that replaces the eyepiece, or use a microscope with a trinocular head and mount the camera there. The images seen through a digital microscope can be saved on a computer file and viewed in a computer monitor. It is the perfect educational tool because the specimen can be viewed by a lot of people simultaneously.