Eye Structure: Cornea-A clear, dome-shaped window in the very front of the eye. It acts as a window for light to pass in. Sclera The sclera is what is known as the white of the eye.It serves as the eye s protective coat. Lens The lens is a crystalline structure that focuses light into the retina.In a healthy eye, the lens changes shape to adjust for close or distance vision.ye Structure: Cornea-A clear, dome-shaped window in the very front of the eye. It acts as a window for light to pass in. Sclera The sclera is what is known as the white of the eye.