Introduction The structures of the eye cornea a transparent structure that allows light to enter the eye pupil iris covered by the conjunctiva, a transparent mucous membrane remember that the conjunctiva lines the inside of the eyelids as well, up to the limbus clinical correlate conjunctivitis which describes inflammation of the conjunctiva lens sclera limbus which is the border of the cornea and sclera medial and lateral canthus Light enters the eye through the cornea and lens which results in an image (inverted and reversed) being formed in the retina the area on the retina with the highest visual acuity is the fovea, which is surrounded by the macula medial (nasal) to the fovea is the optic disc, which is where axons exit forming the optic nerve (cranial nerve II) note that the optic nerve does not have photoreceptors over it, resulting in a small blind spot photoreceptors there are two classes rods provides vision in a low-level light environment does not detect color Retinitis pigmentosa is an inherited disorder characterized by degradation of rod photoreceptors. It presents with progressively deteriorating night vision and peripheral vision cones highly represented in the fovea detect color choroid is a vascular layer of the eye ciliary body is found between the choroid and the iris and is composed of the ciliary muscle which is controlled by the parasympathetic fibers in the oculomotor nerve in order to contract, resulting in miosis ciliary processes which have zonular fibers extending from this structure to the lens forming the suspensory ligament Lens transparent biconvex disc behind the pupil that provides additional refractive power. Is composed of: lens capsule subcapsular epithelium lens fibers disease processes that affect the lens include cataracts - opacifiction of the crystalline lens ectopia lentis - lens dislocation presbyopia - decreased elasticity of the lens leading to impaired accomodation Anterior chamber describes the area behind (posterior) to the cornea and infront (anterior) to the iris Posterior chamber describes the area posterior to the iris and anterior chamber Aqueous humor pathway the ciliary body produces aqueous humor into the posterior chamber which flows through the space between the lens and iris into the anterior chamber and finally drains into the trabecular meshwork and then canal of Schlemm uveoscleral pathway Blood supply an arterial source is from the ophthalmic artery the short posterior, long posterior, and anterior ciliary arteries central retinal artery which supplies the optic nerve occlusion presents as painless, acute loss of vision in the affected eye venous drainage is from the vorticose veins central retinal veins