Axial length increases and related changes in highly myopic normal eyes with myopic complications in fellow eyes

PURPOSE: To determine whether the axial length (AL) in highly myopic normal adult eyes with myopic complications in the fellow eyes increases significantly during a 1-year interval and to investigate the relationships between the changes in the AL and different ocular parameters. METHODS: The medical records of 20 highly myopic normal eyes whose fellow eyes had myopic complications were reviewed. The AL, subfoveal choroidal thickness, height of a posterior staphyloma, and length of the retinal pigment epithelium from the fovea to 3-mm superior, inferior, nasal, and temporal retina were measured twice at an interval of approximately 1 year. The changes in these ocular parameters and their correlations were investigated. RESULTS: The AL increased, the choroid became thinner (both P < 0.001), the superior (P < 0.05) and temporal (P < 0.01) staphyloma height increased, and the superior and temporal retinal pigment epithelial length increased (both P < 0.01). All the changes were significant. Stepwise analyses indicated that the factor most associated with the increase in the AL was the increase in the superior retinal pigment epithelial length (P < 0.001). CONCLUSION: Our results indicate that the AL can increase significantly in highly myopic normal adult eyes during a 1-year interval, and the increase in the posterior staphyloma height is the most likely cause for the increased AL.