Pars plana

The pars plana (Latin: flat portion) is part of the ciliary body in the uvea (or vascular tunic), the middle layer of the three layers that comprise the eye. As a part of the ciliary body, it is about 4 mm long, located near the point where the iris and sclera touch and is scalloped in appearance. The pars plana may not have a function in the post-fetal period, making this a good site of entry for ophthalmic surgery of the posterior segment (pars plana vitrectomy).

References

Anatomy of the globe of the eye
Fibrous tunic (outer)	Sclera Episcleral layer Schlemm's canal Trabecular meshwork Cornea Limbus layers Epithelium Bowman's Stroma Dua's layer Descemet's Endothelium
Uvea/vascular tunic (middle)	Choroid Capillary lamina of choroid Bruch's membrane Sattler's layer Ciliary body Ciliary processes Ciliary muscle Pars plicata Pars plana Iris Stroma Pupil Iris dilator muscle Iris sphincter muscle
Retina (inner)	Layers Inner limiting membrane Nerve fiber layer Ganglion cell layer Inner plexiform layer Inner nuclear layer Outer plexiform layer Outer nuclear layer External limiting membrane Layer of rods and cones Retinal pigment epithelium Cells Photoreceptor cells (Cone cell, Rod cell) → (Horizontal cell) → Bipolar cell → (Amacrine cell) → Retina ganglion cell (Midget cell, Parasol cell, Bistratified cell, Giant retina ganglion cells, Photosensitive ganglion cell) → Diencephalon: P cell, M cell, K cell, Muller glia Other Macula Foveola Fovea centralis Parafovea Perifovea Optic disc Optic cup Ora serrata
Anatomical regions of the eye	Anterior segment Adnexa Fibrous tunic Anterior chamber Aqueous humor Iris Posterior chamber Ciliary body Lens Capsule of lens Zonule of Zinn Posterior segment Vitreous chamber Vitreous humor Retina Choroid
Other	Keratocytes Ocular immune system Tapetum lucidum Eye care professional Eye disease Refractive error Accommodation Physiological Optics Visual perception