Optical coherence tomography (OCT) is a powerful imaging technique that provides cross-sectional imaging of tissues. Among several implementations of OCT, spectral-domain OCT (SD-OCT) provides high-resolution, high-sensitivity, and high-speed imaging. Such implementations enable visualization of the microstructures of the human eye by noninvasive and noncontact equipment. The high sensitivity of OCT detection enables imaging of structures with very low optical scattering, such as the retina. The high axial and lateral resolution enables the precise morphological investigation of various pathological conditions. Tumors that are too small (<1.0 mm in thickness) to be adequately identified by ultrasonography (such as choroidal nevi) can be adequately imaged and objectively measurable by enhanced depth imaging (EDI) EDI OCT techniques.