Longitudinal change of refraction over at least 5 years in 15,000 patients.

BACKGROUND: To report the natural, longitudinal history of shifts in refractive errors in different age groups in a large western European cohort over at least 5 years in the same patients.
METHODS: The electronic database of a large regional clinic containing 225,000 patients was searched for records of patients with a follow-up of at least 5 years, excluding all patients who had received any surgical interventions in any eye. This search retrieved 15,799 patients aged 3 months to 79 years (median 37.8 years) with refractive follow up of at least 5 years (mean 8.8 years) and no surgical interventions. Differences in spherical equivalents (sum of sphere +1/2 cylinder) and cylinder between first and last visit in the same patients in only the right eye were calculated, and used as the measure of refractive shift. Subsequently differences in change between the right and left eye were also determined.
RESULTS: Refractions were found to be mostly stable from 25 to 39 years (n = 3,155 right eyes), with 50% of these patients not changing their refraction. In patients aged 20-24 (n = 825 right eyes), only 39% of the refractions remained stable, whereas 49% experienced a myopic shift. In the age group 40-69 years (n = 6,694), 40-45% remained stable, with an increase in hyperopic shifts. Eighty-five percent of all patients had bilateral symmetric shifts, and 61% showed stable cylindrical values.
CONCLUSIONS: This report documents clinical relevant changes in spherical equivalents in all age groups within 5 to 10 years in the largest examined European cohort. Refractive surgery patients in particular should be selected accordingly, and be informed about the physiological changes which might still occur during their lifetime.