Perspective: visual acuity-keeping it clear.

Research and clinical papers in the ophthalmic literature commonly report visual acuity data. There is considerable variation in the way visual acuity measurements are expressed, and frequently, the charts and the procedures used for the visual acuity testing are inadequately described. Materials and methods can significantly affect visual acuity scores. Contributions to the scientific and professional literature should provide enough detail about their methodologies to allow others to replicate their studies. Here we call for authors and clinicians to be more careful about defining their term, to specifically identify their testing materials, and to give detailed descriptions of their methods of testing.