The eye is a special organ, and due to its medium clarity, a complete examination of all the intraocular tissues can be achieved, including the retina and the vitreous. Within the diseases that affect the posterior segment of the eye, it is important to locate the primary site of the disease, which can be in the choroid, the retinal pigment epithelium, the retina, or the vitreous. The correct identification of the primary site of the disease leads to appropriate diagnosis, treatment, and prognosis of the disease for the patient. It is important to understand that different conditions affect the retina, mainly congenital conditions, retinal degenerations, macular degenerations, infections and inflammatory conditions, retinal dystrophies, and vascular disorders. In recent years, technological advances in diagnostic methods, medical therapies, and surgical techniques have revolutionized the medical practice for retinal diseases. The most common diseases affecting the retina and vitreous and their pathology are discussed in this chapter.