Which tool is typically used to assess visual field loss?

Perimetry is the standard tool used to assess visual field loss. This method involves measuring an individual's entire field of vision, allowing for the detection of blind spots or visual field impairments, which can be critical in diagnosing various eye conditions, such as glaucoma or retinal diseases. The test is typically conducted using a perimetry machine that presents visual stimuli in different areas of the visual field to determine whether the patient can see them.

While other tools described have important functions in the field of eye care, they do not specifically measure visual field loss. An ophthalmoscope is designed for viewing the interior structures of the eye, such as the retina and optic nerve. A tonometer measures intraocular pressure, which is important for screening glaucoma but does not assess the visual field itself. Lastly, a biomicroscope allows for a detailed examination of the anterior segment of the eye and can help diagnose conditions affecting those structures but, again, does not measure the field of vision. Therefore, perimetry is the correct choice for assessing visual field loss.