Purpose: To assess enhanced depth imaging optical coherence tomography (EDI-OCT) visualization of deep posterior pole structures and retrobulbar tissues in myopic eyes and evaluate ocular structural elements that influence this capability.
Methods: Thirty consecutive myopic eyes (>-6 diopters) from 21 patients were enrolled. Exclusion criteria included any pathological condition affecting the posterior pole. Patients underwent biometry to assess axial length, and irises were classified as darkly or lightly pigmented. EDI-OCT scans were obtained by spectral-domain OCT to image posterior pole and retrobulbar structures. Choroidal thickness was measured manually, and for eyes in which the sclera was fully visible, scleral thickness was also measured manually. The influence of central retinal thickness, axial length, refractive error, mean choroidal thickness, mean scleral thickness, and iris pigmentation on EDI-OCT visualization of structures beyond the choroid was tested.
Results: Choroidal thickness was measurable in all eyes. In 11 of 30 eyes, the sclera was not completely visible (group 1). In 19 eyes, the full scleral thickness was measurable (group 2). In seven of the group 2 eyes, the full sclera was the deepest structure detected. In the remaining 11 eyes, deeper structures were visible. Choroidal thickness was the only parameter that correlated with the ability to visualize the full sclera (P < 0.001) and deeper structures (P = 0.044).
Conclusions: The full thickness of the choroid was visualized by EDI-OCT in all eyes. Full thicknesses of the sclera and retrobulbar structures were not always visible. Choroidal thickness was the only parameter that significantly correlated with EDI-OCT visualization of deeper structures.