An historical review of optometric principles and techniques.

Beginning with the seventeenth century, when the main scientific foundations were laid, an account is given of the development of various clinical techniques for the assessment of visual acuity and ametropia. Both subjective and objective methods of refraction, with associated instrumentation, are reviewed. Among the more recent techniques described are meridional refraction, astigmatic decomposition, and photorefraction. In various fields, some little known contributions of particular interest are brought to light.