Figure 2 A three dimensional plot of spherical and cylinder refraction against visual acuity for right eye data of the 3 year old (top) and 4 year old children (bottom). Data are shown in the refractive categories of normal, borderline, and abnormal. A child's refraction was categorised on the basis of the eye with the greatest error. All vision scores are uncorrected acuity. Refraction values shown are for full cycloplegic refraction with allowance for working distance removed.