SHG and Multiphoton Fluorescence Imaging of the Eye

As the organ responsible for vision, the eye plays a vital role in our communication with the external world. Among the intricate components that constitute the eye, collagen-rich cornea is the key optical element responsible for most of the eye’s refractive properties. Although the cornea only represents one-sixth of the outer coating of the eye, its dome-shaped and optically transparent structure contributes to more than two-thirds of the eye’s focusing power. In addition to its collagen content, corneal epithelium is maintained by stem cells located at limbus, which constitutes the peripheral boundary of the cornea. Beyond the limbus, the sclera forms the remaining ocular surface and is responsible for structural integrity and protection of intraocular contents. Like the cornea, the sclera is covered by the epithelial conjunctiva and is mainly composed of collagen bers. Nonetheless, it is the unique alignment of the collagen bers that is responsible for corneal transparency [1, 2].