Which instrument would not be used for measuring intraocular pressure?

The sphygmomanometer is an instrument specifically designed for measuring blood pressure, not intraocular pressure. It assesses the pressure within the arteries, which is unrelated to the pressure inside the eye. Intraocular pressure (IOP) is typically measured using instruments that are specifically designed for this purpose, such as tonometers and applanation devices.

Tonometers and applanation devices are both integral to measuring IOP directly. Tonometers come in various forms, including non-contact and contact types, that help clinicians assess the pressure within the eye. Similarly, an applanation device is often used in conjunction with a slit lamp to measure IOP by applying a small amount of force to flatten a part of the cornea.

Perimeters measure the visual field, providing data on a patient's peripheral vision, which does not include intraocular pressure measurements.

In summary, the ability to distinguish between these instruments is essential in ophthalmology, as they each serve different functions, and understanding their purposes is critical for accurate assessments and patient care.