Axial length changes in highly myopic eyes and influence of myopic macular complications in Japanese adults

PURPOSE To investigate changes of the axial length in normal eyes and highly myopic eyes and influence of myopic macular complications in Japanese adults. STUDY DESIGN Retrospective longitudinal case series. METHODS The changes in the axial length of 316 eyes from 316 patients (mean age, 63.8 ± 9.0 years; range, 34-82; 240 females) examined using IOLMaster with a follow-up period of at least 1 year were studied. This study included 85 non-highly myopic eyes (|refractive error| ≤ 5 diopters; 63 females; non-highly myopic group), 165 highly myopic eyes (refractive error ≤ -6 diopters or axial length ≥ 26 mm; 124 females) without macular complications (no complications group), 32 eyes (25 females) with myopic traction maculopathy (MTM group), and 34 eyes (28 females) with myopic choroidal neovascularization (CNV group). RESULTS All groups showed a significant increase in the axial length during the follow-up period (mean follow-up, 28.7 ± 16.8 months; range, 12-78) (P < 0.01). Changes in the axial length/year in the no complications group (0.041 ± 0.05 mm) were significantly greater than those in the non-highly myopic group (0.007 ± 0.02 mm) (P < 0.0001). Furthermore, changes in the CNV group (0.081 ± 0.04 mm) were significantly greater than those in the no complications (P < 0.0001) and MTM (0.040 ± 0.05 mm) (P = 0.0059) groups, whereas no significant difference was found between the changes in the MTM and no complications groups (P = 0.91). Multiple regression analyses indicated that CNV eyes (P < 0.0001) and female patients' eyes (P = 0.04) showed greater changes in the axial length/year. CONCLUSIONS All groups showed an increase in the axial length, which was greater for highly myopic eyes. In particular, CNV eyes showed greater increases, indicating that larger changes in the axial length may require careful follow-up.