Objective: To examine the change of the axial length measured by IOL Master in adults with high myopia during a 2-year period.
Design: Open-label, consecutive, prospective longitudinal case series.
Methods: One hundred and eighty-five eyes of 185 consecutive patients with bilateral high myopia (myopia ≤ -6 diopters (D) or axial length ≥ 26.5 mm) were studied. The mean age of the patients was 48.4 ± 12.2 years, with a range of 22 to 84 years. The axial length, the anterior chamber depth, and the radius of curvature of the cornea were measured by IOL Master at the initial examination and at 2 years after the first visit. The significance of the changes in the axial length after the 2-year periods was determined. Multiple regression analyses were performed to identify the factors which were significantly associated with the increase of the axial length.
Results: The mean axial length increased significantly from 29.35 ± 1.80 mm to 29.48 ± 1.85 mm in 2 years, a mean increase of 0.13 mm with a range of -0.12 to 1.10 mm. The difference in the increase of the axial length between the patients with and without a posterior staphyloma was not significant. Among the possible explanatory factors, age, axial length, anterior chamber depth, the radius of curvature of the cornea, and intraocular pressure at the initial examination, the increase in the axial length was significantly and positively correlated with the axial length at the initial examination.
Conclusions: The measurement by IOL Master in a large population of highly myopic patients clearly showed that the axial length continued to increase in a span of 2 years even in the 4th decade of life. The eyes with longer axial length showed a greater increase of axial length, suggesting the possibility that the more myopic eyes become more myopic with increasing age.