The role of axial length and keratometry in the follow-up of myopic children

Abstract

Since increased rates of axial elongation are the primary cause of school myopia, following up axial length changes may be valuable in clinical practice. Recently developed curves of ocular growth for schoolchildren allow us to know in which percentile of normal growth is a particular child under follow up. As girls have shorter eyes with more curved corneas than boys, the published axial growth curves were split by gender. Corneal power is also a determinant of refraction. Keratometry is normally distributed in the myopic population around a mean of 43.00D. Some myopic eyes have flat corneas and others have steep corneas. Longer eyes are more prone to developing myopic maculopathy in adult years. If a mild myopic child has flat corneas near 40.00D, one can assume that these eyes may be 1 mm longer than usual by previous emmetropization mechanisms acting in the first years of life, well before myopia developed. In clinical practice, after subjective and cycloplegic refractive error has been evaluated, keratometry and axial length measurements are most necessary to know how any given eye has achieved its particular refractive error. We suggest that, alongside monitoring axial growth changes, keratometry is also considered at the first visit of a myopic patient to determine whether the cornea is either normal, or unusually flat or steep.