Certified Ophthalmic Assistant Practice Exam (2)

The thickest layer of the cornea is called the stroma. The cornea is made up of five layers: epithelium, Bowman's layer, stroma, Descemet's membrane, and endothelium. The stroma is the middle and thickest layer of the cornea, comprising about 90% of its thickness. It is primarily made up of collagen fibers arranged in a specific way to maintain transparency and strength in the cornea. The other options are incorrect because: - Canthi are the corners of the eye where the upper and lower eyelids meet; they are not a layer of the cornea. - Aqueous humor is the clear fluid filling the space in the front of the eye, behind the cornea and in front of the lens; it is not SAMPLEa layer of the cornea. - The iris is the colored part of the eye that controls the size of the pupil and the amount of light entering the eye; it is not a layer of the cornea.