Unaided Visual Acuities Correlated with Refractive Errors

Parameters Associated with the Different Astigmatism Axis Orientations

“…Those who read the 20/20 line with not more than one mistake were assumed to have no refractive error. 19 In subjects using optical correction, those who missed no more than one letter on the 20/20 line were assumed to be properly refracted. Other candidates underwent subjective noncycloplegic refraction.…”

Prevalence of High Astigmatism, Eyeglass Wear, and Poor Visual Acuity Among Native American Grade School Children

“…However, little empiric data have been published concerning the effects of uncorrected astigmatism on visual acuity. [15][16][17] The purpose of the present study is to examine the prevalence of astigmatism, rate of eyeglass wear, and the effects of astigmatism on visual acuity across a broad age range in grade school children who are members of the Tohono O'odham Nation, a Native American tribe in which a high prevalence of astigmatism has been reported. 7,8,10 We report the visual acuity results for the overall sample to determine the "everyday" acuity and the prevalence of poor visual acuity in this sample of children.…”

Phenomenological model of visual acuity

“…This somewhat restricts the utility of this representation, but we have still chosen to keep this data for two reasons. First, because contrary to what happened in other studies such as Pincus's, 9 the subject accommodation was not blocked; therefore, in Peters's cohort the subjects may compensate positive defocus by the use of accommodation (this can be readily seen in the plots of Peters's work 10 ). Second, although Peters's representation of V may be inaccurate at some places, the source for his data, the large and thorough Orinda study, should provide overall meaningful information.…”

“…Among the studies with a large numbers of participants, Pincus 9 measured and tabulated the unaided visual acuity of a population of around 7600 young subjects was. Another classical study on the relationship between refractive blur and visual acuity is the Orinda Vision Study reported by Peters.…”