are called hyalocytes. The lens zonular fibers represent the tertiary vitreous.
Congenital Anomalies
Persistent Fetal Vasculature
Persistent fetal vasculature (PFV; previously known as persistent hyperplastic primary vitreous, or PHPV) is characterized by the persistence of variable components of the primary vitreous and is most often unilateral. In most cases of clinically significant PFV, a fibrovascular plaque in the retrolental space extends laterally to involve the ciliary processes, which may be pulled centripetally by traction from the fibrovascular tissue. The clinical and gross appearance of elongated ciliary processes results. The anterior fibrovascular plaque is generally contiguous posteriorly with a remnant of the hyaloid artery that may attach to the optic nerve head (Fig 10-1). Involvement of the posterior structures may be more extensive, with tractional detachment of the peripapillary retina resulting from traction from preretinal membranes. The lens is often cataractous, and nonocular tissues such as adipose tissue and cartilage may be present in the retrolental mass. Eyes affected by PFV are often microphthalmic. See also Chapter 19 in this volume and BCSC Section 6, Pediatric Ophthalmology and Strabismus.
Bergmeister Papilla
Persistence of a small part of the posterior portion of the hyaloid artery is referred to as a Bergmeister papilla. This anomaly generally takes the form of a veil-like structure or a fingerlike projection extending anteriorly from the surface of the optic nerve head.
Mittendorf Dot
The hyaloid artery attaches to the tunica vasculosa lentis just inferior and nasal to the center of the lens. With regression of these vascular structures, it is not uncommon to see a focal lens opacity at this site, which is referred to as a Mittendorf dot (see Fig 2-41 in BCSC Section 2, Fundamentals and Principles of Ophthalmology).
Prepapillary Vascular Loops
Retinal vessels may grow into a Bergmeister papilla and then return to the optic nerve head, creating the appearance of a vascular loop. These loops should not be mistaken for neovascularization of the optic nerve head. See Fig 16-5 in BCSC Section 12, Retina and Vitreous.
Vitreous Cysts
Vitreous cysts generally occur in eyes with no other pathologic findings, but they have been seen in eyes with retinitis pigmentosa, those with uveitis, and eyes with remnants of the hyaloid system. Histologic studies have suggested the presence of hyaloid remnants in the vitreous cysts. The exact origin of the cysts is not known.