Evaluating the Volume of Eyes With Pathologic Myopia Using 3D MRI.

Abstract

Purpose: To determine the volume of eyes and its relationship to the shape and the presence of posterior staphylomas in patients with high myopia (HM).

Methods: We studied 370 eyes of 199 patients with HM (refractive error >8.00 diopters [D] or an axial length ≥26.5 mm) and 44 eyes of 35 control patients without HM (refractive error from -7.50 to +2.50 D). Magnetic resonance imaging (MRI) of the ocular orbit was used to measure the volume of the eye using three-dimensional (3D) MRI. Reconstructed 3D images of eye were classified according to symmetry and steepness of the posterior curvature.

Results: The mean volume was 12.42 ± 2.40 mL of the 370 HM eyes and 9.67 ± 1.41 mL of the 44 non-HM eyes. Thus, the volume of the HM eyes was 1.3 times larger than the mean volume of the non-HM eyes. The mean volume of the eye was significantly smaller in the cylindrically shaped and larger in barrel-shaped eyes than the eyes with other shapes. The mean eye volume in the HM eyes with a posterior staphyloma was not significantly different from that of HM eyes without a posterior staphyloma.

Conclusions: The volume of HM eyes is larger than non-HM eyes and is associated with steepness of posterior curvature but not with the presence of a posterior staphyloma, suggesting that local outward protrusion of the posterior eye wall is not directly caused by global expansion of eyes and should be monitored specifically in HM eyes.