Which piece of equipment is commonly used for measuring intraocular pressure?

The tonometer is specifically designed to measure intraocular pressure (IOP), which is crucial in diagnosing and managing conditions like glaucoma. It works by assessing the eye's resistance to indentation, thus providing a direct measurement of pressure within the eye. Accurate measurement of IOP is vital for evaluating the health of the eye, particularly in patients at risk for optic nerve damage.

In contrast, the other pieces of equipment serve different purposes. The ophthalmoscope is used for examining the interior structures of the eye, particularly the retina and optic nerve, but it does not measure pressure. The autorefractor helps in determining a person’s refractive error by automating the measurement of how the eye focuses light, but it is not related to IOP measurement. The slit lamp is a diagnostic tool that provides a magnified view of the eye's anterior segment, aiding in the examination of the cornea, lens, and anterior chamber, but it also does not measure intraocular pressure directly. Thus, the tonometer is uniquely suited for assessing IOP, making it the correct answer.