Changes in ocular astigmatism with age: A longitudinal study

Purpose To investigate changes in astigmatism with age. Are changes from with‐the‐rule (WTR) in younger ages to against‐the‐rule (ATR) in older patients mediated through oblique astigmatic axes or spherical prescriptions, and at what ages do these changes occur? Methods Prescription data were gathered retrospectively from one optical practice belonging to a large multiple group in the UK. Longitudinal assessments were made of the changes in astigmatism for 326 patients (mean age at first prescription 46 years, range 28–69 years) and 640 eyes through their recorded prescription history (median 20 years of prescription data per participant, IQR 19–22 years, range 18–29 years). Results Changes in small degrees of astigmatism (0.25 or 0.50 DC) from WTR to ATR were more than three times more likely to pass through an oblique cylinder axis as through a spherical prescription (56 vs. 16, χ12 = 22.2, p