Cornea. Light micrograph of a section through a cornea, the transparent region at the front of the eye. The outer surface of the cornea is a stratified epithelium (dark pink, upper frame) about five cells thick. The epithelium is supported by a basement membrane known as Bowman's membrane (solid blue line, across centre). Beneath this lies the substantia propria (blue/white), the dense collagenous connective tissue that constitutes the bulk of the cornea. Light entering the eye is bent by the cornea. This assists in the focusing of light onto the retina. Magnification unknown.