Time-Course Change in Eye Shape and Development of Staphyloma in Highly Myopic Eyes

To quantitatively assess the posterior pole shape change in highly myopic eyes and to investigate the factors determining the speed of shape change.

Local curvature of the Bruch's membrane on the optical coherence tomography image was measured at intervals of 1 μm, and the mean curvature and curvature variance were calculated for 1094 eyes with an axial length of ≥26 mm. Speed of shape change was calculated using two points of mean curvature and curvature variance, and compared according to age, sex, axial length, and baseline eye shape.

The posterior pole shape of females changed significantly greater than males (P < 0.01). Protruding change through the mean curvature was the greatest in the eyes with an axial length of ≥28 mm and <29 mm, while undulating change through the curvature variance became greater with axial length elongation in the eyes with an axial length of <29 mm and showed similar change in the eyes with an axial length of ≥29 mm. The eyes with a flatter shape at baseline tended to show a slow shape change, whereas those with moderate shape deformation at baseline showed faster shape change.

Quantitative evaluation of posterior pole eye shape clearly demonstrated significant time-dependent protruding and undulating changes in highly myopic eyes. Sex, axial length, and baseline posterior pole eye shape significantly affected speed of the posterior pole shape change. Our findings will facilitate risk assessment of staphyloma-associated complications in highly myopic eyes through measurement of speed of the posterior pole shape change.