Wellsworth Skeffington Cross Cylinder Test

Historical Significance: The dynamic cross cylinder test was a commonly used clinical procedure used to assess the accommodative response subjectively. Astigmatism is induced with the crossed cylinder lenses, and the patient's subjective response to a rectilinear target indicates whether a lead or lag of accommodation exists. Spherical lenses are introduced during this subjective technique to quantify the accommodative error. The test seems attributable to US optometrist Arthur Skeffington. Arthur Marten Skeffington (1890 - 1978) was an American optometrist known to some as "the father of behavioral optometry". Skeffington has been credited as co-founding the Optometric Extension Program with E.B. Alexander in 1928. The OEP devised and promoted a 21 point technique for the evaluation of binocular function and this test was one of the 21 tests. This approach was popular among many optometrists in the USA, although it was regarded sceptically by those who were more academically inclined and looked for a solid theoretical and evidence foundations for clinical tests. More information on this test can be found in The Skeffington perspective of behavioral model of optometric data analysis and vision care by Earl P Schmitt 2006.