What test is used to measure central visual acuity?

The Snellen chart is the primary tool used to measure central visual acuity. It consists of a series of letters that decrease in size, allowing an eye care professional to assess the sharpness or clarity of vision at a standardized distance. When a patient reads the smallest line of letters they can see clearly, their visual acuity can be quantified and recorded, usually as a fraction (for example, 20/20 vision). This measurement represents the ability to discern detail at a distance.

In contrast, the Amsler grid is used to assess macular function and detect distortions in the central vision but does not measure visual acuity directly. The visual field test evaluates the peripheral vision rather than the sharpness of central vision. Ophthalmoscopy is a diagnostic technique used to examine the interior of the eye, including the retina and optic nerve, but it does not measure visual acuity itself. Understanding the specific purpose of each of these tests highlights why the Snellen chart is the correct answer for measuring central visual acuity.