ABSTRACT
The measurement of visual acuity (VA) is an essential part of the ophthalmological examination, and it represents the most common useful test for assessing visual function. In clinical practice, the primary need is to document the occurrence or evolution of pathology; and in clinical trials or research projects, the need is to perform a reliable and reproducible baseline and evaluation of outcome. In refractive surgery, it is relevant to measure the best-corrected VA before and after surgery, to rule out any pathology other than refractive error, and to analyze differences and changes over time.
