In addition to checking your vision, your eye doctor will also check the health of your eye. External examination of the eye includes evaluation of the cornea, eyelids, conjunctiva and surrounding eye tissue using bright light and magnification.
Evaluation of the lens, retina and posterior section of the eye may be done through a dilated pupil to provide a better view of the internal structures of the eye.
Measurement of pressure within the eye (called tonometry) is performed. Normal eye pressures range from 10 to 21 millimeters of mercury (mm Hg), averaging about 14 to 16 mm Hg. Anyone with eye pressure greater than 22 mm Hg is at an increased risk of developing glaucoma, although many people with normal pressure also develop glaucoma.
— Source: American Optometric Association