“…The human eye is covered of layers and internal structures, each of which performs different functions [19] . Anterior segment of the eye involves of front one-third of eye that mainly includes pupil, cornea, iris, ciliary body, aqueous humor, and lens while the posterior segment consists of the back two-thirds of the eye that includes vitreous humor, retina, choroid, macula, and optic nerve (Figure 1) [20,21] . The cornea is the most anterior part of the eye, in front of the iris and pupil [22] .…”