To study anisometropia of spherical equivalent and astigmatism from the onset of myopia at school age to adulthood.
A total of 240 myopic schoolchildren (mean age 10.9 years), with no previous spectacles, were recruited during 1983-1984 to a randomized 3-year clinical trial of bifocal treatment of myopia. Examinations with subjective cyclopedic refraction were repeated 3 years later (follow-up 1) for 238 subjects and thereafter at the mean ages of 23.2 (follow-up 2) and 33.9 years (follow-up 3) for 178 and 134 subjects. After exclusions, the 102 subjects who attended all three follow-ups were included in the analyses. Corneal refractive power and astigmatism and anterior chamber depth was measured with Pentacam topography and axial length with IOL master at study end. Prevalence and changes in anisometropia of spherical equivalent (AnisoSE) and astigmatism (AnisoAST) and their relationships with refractive and axial measures were studied.
Mean (±SD) of spherical equivalent (SE), AnisoSE and AnisoAST increased from baseline to follow-up end from -1.44 ± 0.57 D to -5.11 ± 2.23 D, from 0.28 ± 0.30 D to 0.68 ± 0.69 D and from 0.14 ± 0.18 D to 0.37 ± 0.36 D, respectively. Prevalence of AnioSE, =1 D, increased from 5% to 22.6% throughout follow-up. Higher AnisoSE was associated with SE in the less myopic eye at baseline and at follow-up 1, and with SE in the more myopic eye in follow-ups 2 and 3 in adulthood. At study end, AnisoSE was associated with the interocular difference in axial length (AL) (r = 0.612, p